Symposium Organizers
Larry A. Nagahara National Cancer Institute
Robert Sinclair Stanford University
Rashid Bashir University of Illinois, Urbana-Champaign
Thomas Thundat Oak Ridge National Laboratory
Wenbin Lin University of North Carolina, Chapel Hill
QQ1: Nanofunctional Materials for Biomedical Applications
Session Chairs
Wenbin Lin
Larry Nagahara
Monday PM, November 29, 2010
Grand Ballroom (Sheraton)
9:00 AM - QQ1.1
Hybrid Silica-coated Plasmonic/Magnetic Biomarkers.
Georgios Sotiriou 1 , Ann Hirt 2 , Pierre-Yves Lozach 3 , Alexandra Teleki 1 , Frank Krumeich 1 , Ari Helenius 3 , Sotiris Pratsinis 1
1 ETH Zurich, Particle Technology Laboratory, Zurich Switzerland, 2 ETH Zurich, Institute of Geophysics, Zurich Switzerland, 3 ETH Zurich, Institute of Biochemistry, Zurich Switzerland
Show AbstractHybrid magnetic/plasmonic nanoparticles possess properties originating from each individual material. Such properties are beneficial for biological applications including bio-imaging, targeted drug delivery, in vivo diagnosis and therapy. Limitations regarding their stability and toxicity, however, challenge their safe use. Here, the one-step flame synthesis of composite SiO2-coated Ag/Fe2O3 nanoparticles is demonstrated. The hermetic SiO2 coating does not influence the morphology, the superparamagnetic properties of the iron oxide particles and the plasmonic optical properties of the silver particles. It does prevent, however, the release of toxic Ag+ ions from the nanosilver surface and reduces the interaction field among the iron oxide particles, resulting in a stable over 2 days suspensions with no signs of agglomeration (flocculation) and sedimentation. The feasibility of these multi-component nanoparticles with superior properties and performance is explored by their specific binding with live tagged cells, and the detection as well as magnetic manipulation of the latter is demonstrated. Therefore, the hybrid SiO2-coated Ag/Fe2O3 nanoparticles do not exhibit the limiting physical properties of each individual component, while retain all the desired ones, facilitating their safe employment in such bio-applications.
9:15 AM - QQ1.2
Preparation of Thermo-responsive Polymer-coated Gold Nanorods and Their Accumulation to Light Irradiated Site.
Takuro Niidome 1 2 3 , Atsushi Shiotani 1 , Yasuro Niidome 1 , Takeshi Mori 1 2 , Yoshiki Katayama 1 2
1 Department of Applied Chemistry, kyushu University, Fukuoka, Fukuoka, Japan, 2 Center for Future Chemistry, Kyushu University, Fukuoka, Fukuoka, Japan, 3 PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
Show AbstractRod-shaped gold nanoparticles (gold nanorods) have unique optical properties. They show strong absorption band in the near infrared region corresponding to longitudinal surface plasmon oscillation, and, show photothermal effect. Since the near infrared light can penetrate deeply into tissues due to minimum light absorption by intrinsic chromophores, hemoglobin, and water, the gold nanorods are expected as a nanodevice for in vivo imaging and photothermal therapy.
Recently, we succeeded in preparing gold nanorods modified with thermosensitive polymer (N-isopropylacrylamide; NIPAM) gel. However, after intravenous injection of the gel modified-gold nanorods, most of them accumulated to the liver and spleen because the phase transition temperature of the gel layer was lower (34°C) than body temperature of mammals (Kawano et al., Bioconjugate Chem., 20, 209-212, 2009). In this study, we modified the gold nanorods with thermosensitive polymers, of which phase transition temperature was tuned by adding hydrophilic monomer units, then we demonstrated targeting of the gold nanorods to tumor by irradiating near infrared laser light.
To increase the phase transition temperature, hydrophilic monomer (DMAA or AAm) was added to the NIPAM gel on the gold nanorods as a co-monomer. The sizes of the resulting gel-modified gold nanorods were 300 nm in diameter. The phase transition temperatures of copolymerized thermosensitive gels PNIPAM-DMAA and PNIPAM-AAm-coated gold nanorods were shifted to 38°C and 41°C, respectively. After the PNIPAM-AAm-coated gold nanorods were systemically injected into mice that had two tumors in one mouse, the right tumor irradiated using the near-infrared laser for 10 min. At 20 min after the irradiation, 80% of injected dose of the gold was found in blood. The irradiated right tumor contained a larger amount of the gold (20%/g tissue) compared with the other (non-irradiated) tumor (1%/g tissue). These results suggested that accumulation of PNIPAM-AAm-coated gold nanorods in the right tumor was due to photothermal phase transition and aggregation of the gold nanorods induced by the laser irradiation.
9:30 AM - **QQ1.3
Gold Nanocages: A Multifunctional Platform for Nanomedicine.
Younan Xia 1
1 Biomedical Engineering, Washington University, Saint Louis, Missouri, United States
Show AbstractGold nanocages have proven to be a versatile platform for a broad range of biomedical applications, with potential use in numerous areas including: diagnostics and sensing, in vitro and in vivo imaging, and therapeutic techniques. These applications are possible because of the highly favorable properties of gold nanocages, many of which can be tailored for specific applications. In the first part of this talk, I will discuss the most critical properties of gold nanocages for biomedical applications: surface chemistry, localized surface plasmon resonance (LSPR), and morphology. In the second part of this talk, I will discuss how these properties can be harnessed for a selection of biomedical applications in nanomedicine, aiming to give the reader an overview of general strategies as well as highlight some recent advances in this field.
10:00 AM - **QQ1.4
Nanoscale and Microscale Technologies for 3D Cell Culture and Tissue Engineering.
Jackie Ying 1 , Andrew Wan 1
1 , Institute of Bioengineering and Nanotechnology, Singapore Singapore
Show AbstractThe application of nanoscale and microscale technologies to the biomedical field has attracted much interest in recent years, due to the realization that control of cellular behavior, and therefore optimal tissue regeneration, can be achieved by the provision of appropriate interactions between the cells and their extracellular matrix. This talk describes the development of novel matrices for cell culture and tissue engineering based on nanocomposites and microfibers. Specifically, 3D cell culture in a thixotropic, nanocomposite gel with mechanically reversible properties has revealed relationships between stem cell differentiation, extracellular matrix secretions and the mechanical environment of cells. Fibers by a process of interfacial polyelectrolyte complexation can be imbued with biological signals that direct lineage-specific differentiation of stem cells. Assembly of these fibers into higher order structures enables patterned co-cultures with improved cell-cell interactions and cell function.
11:00 AM - **QQ1.5
Designed Fabrication and Assembly of Uniform-sized Magnetite Nanocrystals with Various Sizes and Shapes and Their Applications to Novel MRI Contrast Agents and Related Multifunctional Biomedicine.
Taeghwan Hyeon 1 , Nohyun Lee 1 , Byunghyo Kim 1 , Daishung Ling 1 , Mihyun Park 1
1 School of Chemical and Biological Engineering, Seoul National University, Seoul Korea (the Republic of)
Show AbstractWe developed a new generalized synthetic procedure, called as “heat-up process,” to produce uniform-sized magnetite nanocrystals. We were able to synthesize uniform 11 nm-sized magnetite nanocrystals as much as 1 kilogram-scale from the thermolysis of metal-oleate complexes. We synthesized uniform < 3 nm-sized magnetite nanocrystals and used them for T1 MRI contrast agents. We synthesized 80 nm-sized ferrimagnetic magnetite nanocrystals and successfully applied them for highly sensitive T2 MRI contrast agent for tracking transplanted pancreatic islet cells. Clever combination of different nanoscale materials will lead to the development of multifunctional nano-biomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy. We fabricated monodisperse magnetite nanoparticles embedded in uniform pore-sized mesoporous silica spheres and PLGA polymers for simultaneous MRI, fluorescence imaging, and drug delivery. We synthesized hollow magnetite nanocapsules and used them for both the MRI contrast agent and magnetic guided drug delivery vehicle.
11:30 AM - QQ1.6
Highly Magnetic Iron Carbide Nanoparticles from a Biopolymer Route.
Zoe Schnepp 1 , Stuart Wimbush 2 , Markus Antonietti 1 , Cristina Giordano 1
1 , Max Planck Institute for Colloids and Interfaces, Potsdam Germany, 2 Department of Materials Science and Metallurgy, University of Cambridge, Cambridge United Kingdom
Show AbstractMagnetic nanoparticles have numerous biomedical applications, such as site-specific drug delivery, hyperthermia treatment and as contrast agents for magnetic resonance imaging. By far the most widely used and studied material is iron oxide, but this has the disadvantage of a relatively low saturation magnetization. Metallic iron offers a much higher magnetization, but is unsuitable for medical applications due to its toxicity. An attractive alternative, offering both high magnetization and chemical stability, is iron carbide (Fe3C). Many current routes to Fe3C however, involve costly or hazardous precursors and high energy, multi-step procedures. We report a facile, one-pot synthesis of phase-pure Fe3C nanoparticles (10-30nm) using aqueous precursors. The readily available polypeptide gelatin is used as a reactive template for nucleation of magnetite (Fe3O4) nanoparticles and subsequent carbothermal reduction to Fe3C. A full mechanistic investigation shows how the biopolymer stability, functional groups and elemental composition all balance to create a stable and structurally uniform product. The highly-magnetic nanoparticles described should be of interest for potential biomedical and catalytic applications. In addition, this simple, aqueous route represents a considerable advance on previous methods and could be readily applied to a general synthesis of metal carbide materials.
11:45 AM - QQ1.7
Synthesis and Design of Soft Biodegradable Polymersomes.
Joshua Katz 1 , Daniel Hammer 1 2 , Jason Burdick 1
1 Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2 Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractPolymer-based vesicles or polymersomes are promising materials for applications in drug delivery and medical imaging. A synthetic analog to the liposome, polymersomes have been designed from a wide range of di and triblock copolymers. Especially promising are vesicles on which the hydrophilic block is comprised of PEG, imparting a stealth character for use in vivo. One limitation of many polymers used for polymersomes, though, has been their lack of degradability, a limitation that could prove to be problematic as the technology is developed and subjected to regulatory approval. To address this issue, our lab recently reported vesicles comprised exclusively of poly(caprolactone)-b-poly(ethylene glycol) (PCL-PEG) copolymers, where PCL is degradable and both components are approved by the FDA for human use. PCL-PEG polymersomes demonstrated sustained and controlled release of encapsulated doxorubicin, even though the membranes were of a crystalline nature. Although this design has shown several advantages over non-degradable vesicles, non-crystaline and fluid membranes are desirable to allow the vesicles to deform and move through tight spaces (such as leaky vasculature) in vivo.To address this issue, we have synthesized and developed polymer vesicles in which the PCL block has been replaced by a derivative of caprolactone, 1,4,8-trioxaspiro-[4,6]-9-undecanone (TOSUO), which is noncrystalline as a polymer. The diblock polymer PTOSUO-PEG was prepared by the ring opening polymerization of TOSUO using monomethoxy PEG as the initiator and tin octoate as the catalyst. The polymer (13 kDa PTOSUO, 2 kDa PEG, PDI = 1.20, Tg = -40 oC) spontaneously formed large multilamellar vesicles upon heating of an aqueous film submerged in buffer overnight. As with other polymersome systems, hydrophobic dyes (i.e. nile red) could be loaded near-quantitatively into the membrane of the vesicle, and large hydrophilic dyes could be encapsulated in the interior, both imaged by confocal microscopy. Micropipette aspirations of giant vesicles indicate an area elastic modulus significantly less than that which is found for poly(butadiene)-b-poly(ethylene glycol) and lipid vesicles (15 dyne/cm^2 compared to ~95 and 180 dyne/cm^2, respectively). Cryo-TEM of sonicated films of PTOSUO-PEG showed a mixed population of vesicles and cylindrical micelles.Current research is focusing on blends of PCL and PTOSUO polymers to modulate the overall membrane stiffness. Vesicles with blends of PCL-PEG and PTOSUO-PEG are being fabricated by solvent exchange methods using microfluidic devices. Similarly, copolymers of PCL and PTOSUO are being synthesized to modulate the glass transition temperature of the polymer. It is our goal to develop biodegradable vesicles with membrane stiffnesses similar to that of naturally-occurring lipid vesicles.
12:00 PM - QQ1.8
Size-tunable Highly Luminescent Glass Beads Impregnated with Number-adjusted Quantum Dots and their Application to Biological Imaging.
Norio Murase 1 2 , Ping Yang 1 2 , Masanori Ando 1 2 , Mariko Suzuki 1 , Chie Hosokawa 1 2 , Kazunori Kawasaki 1 2 , Tomoki Kato 1 , Koichi Uegaki 1 , Takahisa Taguchi 1 2
1 Health Research Institute, National Institute of Advanced Industrial Science & Technology, Ikeda Japan, 2 , CREST, Ikeda Japan
Show AbstractWe are creating new materials with dispersed emitting quantum dots (QDs) by utilizing the peculiar reaction properties of glass matrices. We previously prepared strongly emitting glass fibers impregnated with self-assembled QDs, glass beads impregnated both with magnetic nanocrystals emitting QDs. We have now prepared size-controllable glass beads (less than 100 nm in diameter) impregnated with number-adjusted one of two types of QDs (hydrophilic and hydrophobic) for use in biological imaging. Stöber synthesis was used to deposit hydrolyzed alkoxide on the surfaces of the QDs. For hydrophilic CdTe QDs, partial ligand exchange to 3-mercaptoprophltrimethocysilane (MPS) and simultaneous addition of a poor solvent (e.g., ethanol) is the key to maintaining the initial photoluminescence (PL) efficiency and regulating their assembly. One example of the glass beads thus prepared had a diameter of 16 nm and contained three QDs in average. Their PL efficiency was 40% whereas it was initially 46% in colloidal solution. A red-shifted and narrowed PL spectrum was observed after QD impregnation. It is attributed to the high concentration of QDs in the beads. For hydrophobic CdSe/ZnS QDs, surface modification using hydrolyzed tetraethyl orthosilicate (TEOS) and subsequent transfer to the water phase in the presence of hydrolyzed MPS is the key to maintaining the initial PL efficiency and regulating their assembly. One example of the glass beads prepared using these QDs had a diameter of 46±6 nm and contained 22 QDs (mean number). Their PL efficiency was 34% whereas it was initially 35% in colloidal solution. The stability of the glass beads impregnated with CdSe/ZnS QDs was better than that of those with CdTe QDs. The PL intensity from a single glass bead with CdSe/ZnS QDs was proportional to (PL efficiency × number of QDs in one bead) and showed no blinking due to the averaging effect. Furthermore, because of the glass network around the CdSe/ZnS QDs, the Cd2+ released from beads containing them and dispersed in HEPES buffer was less than 10% that for polymer-coated commercial QDs (Q-tracker, COOH-coated QDs and streptavidin-coated QDs). The PL intensity from continuously irradiated glass beads lasted ~100 times longer than for the initial QDs in solution, again due to the glass network. Thus, glass beads impregnated with CdSe/ZnS QDs are well suited for biological imaging.
12:15 PM - QQ1.9
Bio-imaging for Targeted Delivery of Hyaluronic Acid Derivatives to the Livers in Cirrhotic Mice Using Quantum Dots.
Sang-Jun Park 1 , Ki Su Kim 1 , Wonhee Hur 2 , Eun Ji Goh 1 , Seung Kew Yoon 2 , Sei Kwang Hahn 1
1 Department of Materials Science and Engineering, POSTECH, Pohang Korea (the Republic of), 2 Department of Internal Medicine & WHO Collaborating Center of Viral Hepatitis, The Catholic University of Korea, Seoul Korea (the Republic of)
Show AbstractLiver fibrosis or cirrhosis is one of the representative liver diseases with a high morbidity and mortality worldwide. Over the past decades, many kinds of anti-fibrotic compounds have been investigated in vitro and in vivo for the treatment of liver cirrhosis. In this work, real time bio-imaging of hyaluronic acid (HA) derivatives was carried out using quantum dots (QDots) to assess the possibility of HA derivatives as target specific drug delivery carriers for the treatment of liver diseases. HA-QDot conjugates with an HA modification degree of ca. 22 mol% was synthesized by amide bond formation between carboxyl groups of QDots and amine groups of adipic acid dihydrazide modified HA (HA-ADH). According to in vitro cell culture tests, HA-QDot conjugates were taken up more to the cells causing chronic liver diseases such as hepatic stellate cells (HSC-T6) and hepatoma cells (HepG2) than normal hepatocytes (FL83B). After tail vein injection, HA-QDot conjugates were target-specifically delivered to cirrhotic liver with a slow clearance longer than 8 days. Furthermore, immunofluorescence and flow cytometric analyses of dissected liver tissues revealed the target specific delivery of HA derivatives to liver sinusoidal endothelial cells (LSEC) and HSC. The results were thought to reflect the feasibility of HA derivatives as novel drug delivery carriers for the treatment of various chronic liver diseases including hepatitis, liver cirrhosis, and liver cancer.
QQ2: Nanofunctional Devices for Biomedical Applications
Session Chairs
Rashid Bashir
Larry Nagahara
Monday PM, November 29, 2010
Grand Ballroom (Sheraton)
2:30 PM - **QQ2.1
Clinical Microfluidics.
Mehmet Toner 1
1 Center for Engineering in Medicine, Massachusetts General Hospital, Charlestown, Massachusetts, United States
Show AbstractBiomedical applications of microfabricated devices is no longer limited to non-living systems as genes-on-a-chip or lab-on-a-chip, recent advances in the understanding of cellular behavior in micro-environments have started to pave the way toward living micro-devices. These emerging devices are expected to become key technologies in the 21st century of medicine with a broad range of applications varying from diagnostic, tissue engineered products, cell-based drug screening tools, and basic molecular biology tools. This presentation will briefly review the literature on the use of microtechnologies in cellular systems and then focus on a number of clinical applications, especially to those in blood diagnostics in cancer, HIV/AIDS and global health, and burns and trauma. The critical components of several microfluidic technologies validated using patients will be discussed within the context of different clinical applications. Special emphasis will be given to the broad range of end-users for clinical microfluidic tools such as highly skilled technical assistants at medical centers of excellence to point-of-care use in resource limited areas for global health.
3:00 PM - QQ2.2
Selective Filopodial Extensions of Human Mesenchymal Stem Cells Along Fibronectin-carbon Nanotube Hybrid Nanostructures.
Seon Namgung 1 , Ku Youn Baik 1 , Taekyeong Kim 1 , Jwa-Min Nam 2 , Seunghun Hong 1 3
1 Physics and Astronomy, Seoul National University, Seoul Korea (the Republic of), 2 Chemistry, Seoul National University, Seoul Korea (the Republic of), 3 Biophysics and Chemical Biology, Seoul National University, Seoul Korea (the Republic of)
Show AbstractRecently, carbon nanotubes (CNTs) have been extensively used in cellular applications such as neural signal amplification, cancer therapeutics, tissue engineering. In spite of these cellular applications of CNTs, the underlying microscopic interactions between proteins and nanostructures are still obscure. Herein, we first reveal that fibronectin (FN), one of the extracellular matrix proteins intermediating cell adhesion, is more activated on the CNTs via force spectroscopy using atomic force microscope (AFM). Using this affinity of FN to CNTs, we develop a general strategy to induce controlled cell adhesion and growth on FN-CNT hybrid nanostructures, which is applicable for diverse cell types including human mesenchymal stem cells (hMSCs). Interestingly, in our experiments, highly selective filopodial extensions following FN-CNT hybrid nanostructures are achieved in a single hMSC. In addition, we unravel the crucial role of FN in FN-CNT hybrid nanostructures for the controlled cell growth. The possible contribution of this strategy to controlled cell growth for various cellular applications will also be discussed.
3:15 PM - QQ2.3
Combinatorial Development of Biomaterials for Stem Cell Engineering.
Ying Mei 1 , Krishanu Saha 2 , Said Bogatyrev 1 , Jing Yang 3 , Andrew Hook 3 , Z. Kalcioglu 1 , Seung-Woo Cho 4 , Maisam Mitalipova 2 , Neena Pyzocha 2 , Fredrick Rojas 1 , Krystyn Van Vliet 1 , Martyn Davies 2 , Morgan Alexander 2 , Robert Langer 1 , Rudolf Jaenisch 2 , Daniel Anderson 1
1 , MIT, Cambridge, Massachusetts, United States, 2 , The Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States, 3 , The University of Nottingham, Nottingham United Kingdom, 4 , Yonsei University, Seoul Korea (the Republic of)
Show AbstractHuman pluripotent stem cells hold enormous potential for applications in regenerative medicine and human disease modeling. They have the unique ability to undergo self-renewal indefinitely in culture and have potential to differentiate into almost all cell types in human body. Such cells can either be derived from human embryos or be ‘reprogrammed’ from patient’s blood, skin, and fat samples. However, current methods to clonally grow them are inefficient and poorly-defined for genetic manipulation and therapeutic purposes. Here I report combinatorial development of synthetic biomaterials that support robust self-renewal of fully dissociated human pluripotent stem cells, preserve a normal karyotype, and maintain full differentiation capacity after prolonged cell culture. To the best of our knowledge, these materials provide the first chemically defined, xeno-free, feeder-free system to support the efficient clonal growth of human pluripotent stem cells at unprecedented high levels. Materials properties including surface topography after protein adsorption, surface wettability, molecular surface chemistry and reduced indentation modulus of all polymeric substrates were quantified using high-throughput methods to develop structure/function relationships between materials properties and biological performance. The studies described here provide a global understanding of relationships between human pluripotent stem cell growth and synthetic materials, as well as a general framework for the development of synthetic surfaces for stem cell culture.
3:30 PM - **QQ2.4
Detection and Analysis of Circulating Tumor Cells.
Siyang Zheng 1
1 Bioengineering Department, Penn State University, University Park, Pennsylvania, United States
Show AbstractEnriching and detecting circulating tumor cells (CTC) from human blood currently poses significant challenges to the evaluation of tumor metastasis. Although there have been a number of technologies designed to improve the ability to identify and monitor CTC in the blood of cancer patients, difficulties with sensitivity, specificity, efficiency, and high costs of materials and reagents continue to limit these efforts. Here, we present an overview of current methodologies for enrichment of CTC; furthermore, a novel membrane microfiltration technology for isolation of CTC in blood by exploiting size differences between tumor and normal blood cells developed by our group will be discussed. We evaluated the sensitivity and efficiency of CTC capture in a model system, and compared the membrane microfilter device with the CellSearch platform, recognized as the “gold standard” for isolation of CTC, in blood samples from patients with cancer. We have demonstrated superior performance over the “gold standard” platform using both well characterized model systems and clinical samples. Moreover, multimarker immunofluorescence (IF) can be performed and evaluated directly on the membrane microfilter device. Our microfilter device is compatible with laser capture microdissection for isolating a subset of captured cells with further downstream analysis such as comparative genomic hybridization analysis. The membrane microfilter device has transformative potential to provide a cheaper, faster, and better alternative to current approaches to CTC isolation, and does not depend on affinity based capture of cells, as do other platforms. A major advantage is that cell characterization can take place directly on the device. Recently we further developed microfilters that can enrich viable CTC from blood, which enables functional assays and CTC drug sensitivity tests. Future efforts using the membrane microfilter devices will focus on the enumeration of CTC as an early indicator of therapeutic efficacy, and on the biological characterization of CTC, including identification of therapeutic targets.
4:30 PM - **QQ2.5
Carbon Nanotube X-ray for Diagnostic Imaging and Radiotherapy.
Otto Zhou 1
1 , Uni of North Carolina, Chapel Hill, North Carolina, United States
Show AbstractX-ray radiation is widely used for medical imaging, radiotherapy and homeland security applications. We developed a carbon nanotube based field emission x-ray technology that can generate temporally and spatially modulated radiation and can be readily gated with physiological signals. The technology has the potential to increase the resolution and scanning speed of today’s tomography scanners and enable new imaging and therapy systems with expanded functionalities. Since the initial conception, the technology has moved from a simple laboratory curiosity to clinical test. In this talk we will introduce the basic technology and describe some of the imaging and therapy systems currently under development. We will further discuss the demand and challenges for the carbon nanotube field emitters imposed by these applications.
5:00 PM - QQ2.6
Large-scale Synthesis of Bio-inert Tantalum Oxide Nanoplatform for X-ray Computed Tomography Imaging and Bimodal Image Guided Sentinel Lymph-node Mapping.
Myoung hwan Oh 1 , Taeghwan Hyeon 1 , Nohyun Lee 1 , Seung Hong Choi 2
1 National Creative Research Initiative Center for Oxide Nanocrystalline Materials and World Class University program of C2E2,School of Chemical and Biological Engineering, Seoul National University, Seoul Korea (the Republic of), 2 Diagnostic Radiology, Seoul National University Hospital, and the Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul Korea (the Republic of)
Show AbstractIn the course of developing diagnostic nanoprobes, nanoparticulated X-ray contrast agents have garnered attentions. However, so far, economically feasible as well as multifunctional X-ray contrast probe nanomaterials have been merely explored. Here we show that bio-inert tantalum oxide nanoparticles are suitable nanoprobes for wide-spread X-ray CT (computed tomography) imaging while being cost-efficient and having the qualification to be a biomedical platform. Tantalum oxide was successfully confined via nanoscale microemulsion method, and its surface was simply modified with various silane derivatives by in situ sol-gel reaction. Using diverse silane chemistry, poly ethylene glycol (PEG) was introduced on the surface to endow the nanoparticles with biocompatibility and antifouling activity. Immobilized fluorescence dye enables the simultaneous fluorescence imaging in addition to X-ray CT imaging. The resulting nanoparticles exhibited remarkable performances in in-vivo X-ray CT angiography and bimodal image-guided lymph-node mapping.
5:15 PM - QQ2.7
Fabrication and Applications of 3D Nanoporous Membranes.
Christina Randall 1 , Kai-Wen Pai 1 , Tanmay Manohar 1 , David Gracias 1
1 , JHU, Baltimore, Maryland, United States
Show AbstractWe describe the fabrication of three-dimensional (3D) membranes with precisely patterned surface nanoporosity and their utilization in size selective sampling and cell culture applications. The membranes were self-assembled as porous cubes from lithographically fabricated two-dimensional templates. By utilizing all of the advantages of conventional fabrication, we are able to precisely control the overall face dimensions (200-500 µm) with monodisperse pore arrays with diameters of 5–10 µm. After assembly, gold (Au) is electroplated onto the surface of the microporous cubes thereby reducing the pores to the nanoscale (<100 nm). The Au coating also enhances the biocompatibility of the membranes and can be readily modified using a variety of thiol coatings to further modify/specialize the devices.As opposed to conventional methods of sampling where filtration occurs by the fluid flowing across a static membrane, we demonstrate sample collection by instead moving the 3D nanoporous membrane through the solution. This setup allows for straightforward sampling in small volumes, with little to no loss of the solvent and solute. Membranes with five porous faces and one open face were moved through fluids to sample and retain nanoscale beads based on pore size. These experiments, along with scanning electron microscopy images of the membranes, allowed us to characterize the resulting pores sizes. This same method was used to sample cells within the membranes. For compatibility testing, sampled cells were retained within unsealed membranes and subsequently cultured using standard cell culture protocols. The cells, stained with Live/Dead assay multiplied within the membranes, filling them and adhering to the surfaces in all three dimensions. Additional cell sampling experiments involved sealing the membranes to entrap the beta cells thus allowing us to investigate the applicability of these 3D nanoporous membranes as cell encapsulation devices.
5:30 PM - QQ2.8
Controlled Behavior of Neural Stem Cells on Carbon Nanomaterials.
Sung Young Park 1 , Dong Shin Choi 1 , Ki-Bum Lee 2 , Seunghun Hong 1 3 4
1 Interdisciplinary Program in Nano-Science and Technology, Seoul National University, Seoul Korea (the Republic of), 2 Department of Chemistry & Chemical Biology, Rutgers, The State Univ. of New Jersey, Newark, New Jersey, United States, 3 Dept. of Physics and Astronomy, Seoul National University, Seoul Korea (the Republic of), 4 Dept. of Biophysics and Chemical Biology, Seoul National University, Seoul, Seoul, Korea (the Republic of)
Show AbstractNeural stem cells (NSCs) have offered great potential owing to the ability to generate neurons and glia in the developing and adult brain. However, for therapeutic applications such as rebuilding damaged nerves, one should be able to precisely control the direction and polarization of individual axonal growth. Here we report a novel method to control NSC behavior using carbon nanomaterials with good biocompatibility. For example, combinatorial carbon nanotube patterns with different shape and size can provide an effective way to control NSC such as directed -orientation and polarization during growth and differentiation. We discuss more result of NSC behavior on carbon nanomaterials, which show promising potentials useful for stem cell research, neural engineering, and advanced tissue engineering.
5:45 PM - QQ2.9
Single Cell Behaviors on Single Electrosprayed Nanofibers with Controllable Large Pore Sizes.
Jong Kyu Hong 1 , Sundararajan Madihally 1
1 Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma, United States
Show AbstractUnderstanding cell-substrate interactions and dynamic changes in cellular activity is of significant importance in a broad spectrum of medicine and engineering. Many 3D culture models exist but they do not replicate the in vivo circumstance for cell and tissue inside animals or humans. Electrospinning has emerged as a technique for tissue regeneration due to the possibility of fabricating nano and microfibers mimicking in vivo condition. However, small pore size of electrosprayed fibers restrict mammalian cells from infiltrating into the sublayers accessing the 3D space. To overcome this barrier, we have recently developed a novel electrospraying process to fabricate the thin layer of polycaprolactone (PCL) fibers with large pore sizes suitable for 3D scaffold in serum media. Furthermore, in this study we address single cell behaviors in serum free media using PCL/gelatin electrosprayed nanofibers with controllable large pore size.Mixture of PCL (Mn =80,000) and gelatin Type A in hexafluoro-2-propanol were used to fabricate PCL/gelatin fibers. The setup of electrospraying consists of a syringe pump, syringe, needle tip, high voltage power supply, earth grounding, and the novel collector or a conventional one. The pore size was controlled by manipulating the deposit volume of polymer solution. The physical properties of fibers were confirmed using SEM, CCD camera, and Sigma Scan Pro software. Statistical analysis was carried out using ANOVA. A value of p ≤ 0.05 was considered statistically significant. The gelatin distribution and fiber stability were confirmed by using CFDA-SE in Krebs Henseleit buffer solution (pH 7.4) at CO2 incubator and 37°C. Adhesion study of human fibroblast for 3, 8, and 24 hr was carried out in serum free media. Cell morphology was confirmed using fluorescent confocal microscopy and SEM.The diameter and shape factors of new fibers appear similar to those of conventional ones. The fiber diameters were estimated to about 700 nm and the shape factors of the fiber pores were about 0.55. The pore sizes of conventional fibers were the same (5 μm) but those of the new fibers were decreased when the deposit volume of the polymer solution were increased from 0.3 via 0.6 to 0.9 μL. The average pore sizes of the new fibers were 339, 129, and 51μm, respectively; they were statistically significant. Gelatin was distributed well in a PCL/gelatin fiber and the fiber was stable under the physiological conditions for two weeks. The fiber with average pore size (129 µm) was used for cell culture study due to the optimized pore size for 3D scaffold (about 100-150 μm). The shape of cells were triangular, quadrangular, and elliptical. Cell shapes were dependent on the configuration of the fibers, not the period of cell culture. Thus, the in vitro cell behavior model on 3D nanofibers with controllable large pore size will have a great potential to use for other cell behavior studies along with various biomaterials and cells.
QQ3: Poster Session: Nanofunctional Materials for Biomedical Appications: Synthesis, Characterization, and Properties
Session Chairs
Rashid Bashir
Wenbin Lin
Larry Nagahara
Robert Sinclair
Thomas Thundat
Tuesday AM, November 30, 2010
Exhibition Hall D (Hynes)
9:00 PM - QQ3.1
Modular Compact Ligands for Biocompatible Semiconductor Quantum Dots and Gold Nanoparticles with Extended pH and Ionic Stability.
Kimihiro Susumu 1 , Eunkeu Oh 1 , James Delehanty 2 , Igor Medintz 2
1 Division of Optical Sciences, Naval Research Laboratory, Washington, District of Columbia, United States, 2 Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, District of Columbia, United States
Show AbstractBiocompatible nanoparticle (NP) materials have recently attracted significant attention due to increasing interest in their use for cellular labeling and in vivo imaging studies. Semiconductor quantum dots (QDs) and gold nanoparticles (AuNPs) with good pH and ionic stability as well as small hydrodynamic volumes are particularly useful for these applications. Over the past several years, we have developed modular poly(ethylene glycol) (PEG) ligands appended with a dihydrolipoic acid (DHLA) anchoring group at one end and a variety of functional groups at the other end for biocompatible NPs. The dithiol group of the DHLA unit provides enhanced binding to QD and AuNP surfaces, while the PEG chain extends the pH stability of NPs. In an effort to reduce the size of the NPs without sacrificing colloidal stability, we have recently designed and synthesized a new class of DHLA-based compact multifunctional ligands displaying zwitterionic properties with both amino and carboxyl groups incorporated for aqueous solubility and biofunctionalization. The molecular weight of the new ligand is less than half that of the previous DHLA-PEG series, resulting in an overall reduction in the NP size and the hydrodynamic volume. QD dispersions capped with the new ligands were found to be colloidally stable and remained fluorescent over the range from pH 4 to pH 12 for at least 2 months. Our new compact ligands are small enough to allow oligohistidine-tagged globular proteins to directly bind on the QD surface while previously developed PEG ligands hampered direct conjugation between QDs and His-tagged proteins. The direct conjugation of QD surface and His-tagged mCherry was confirmed by agarose gel electrophoresis and fluorescence resonance energy transfer (FRET) studies. Since the compact ligand also has a carboxyl group available for bioconjugation, we demonstrated EDC coupling of the QDs with amine-terminated rhodamine dyes. The fluorescence spectra of the QD-dye conjugate showed FRET from the QD donor to the dye acceptor. This FRET data indicates that the dye was successfully conjugated with the QD and was located close enough to exhibit efficient FRET. We will discuss details of ligand design, synthesis and colloidal stability of the NPs, along with cellular delivery applications for these new NP materials.
9:00 PM - QQ3.11
Fabrication of Dispersed LaOCl Nanoparticles for Bioimaging under near Infrared Excitation.
Yuji Sawayama 1 , Hiroshi Hyodo 1 , Kohei Soga 1
1 Materials Science and Technology, Tokyo University of Science, Chiba Japan
Show AbstractLanthanum oxychloride (LaOCl) doped with rare-earth ions is one of the rare-earth doped ceramic nanophosphor (RED-CNP), which can emit efficient near infrared (NIR) and visible upconversion emission under NIR excitation. The use of the RED-CNP for fluorescence bioimaging is now attracting attention since it can avoid the current problems of fluorescence bioimging such as color fading and scattering. LaOCl with particle size of tens nanometer for the use in bioimaging were prepared by dissolving hydrated chlorides of lanthanum (LaCl3) of LaOCl-LaCl3 core-shell particles in water , which were synthesized through a self-hydrolysis process of LaCl3 [1]. As nanoparticles with particle a size of tens nanometer are easily agglomerated, dispersion stability is one of the most important issue for the RED-CNP. In this study, the dispersion was achieved by modifying the CNP with poly(ethylene glycol)-b-poly(acrylic acid) (PEG-PAAc). Core-shell particles was directly added to the solution contained PEG-PAAc and poly(ethylene glycol) (PEG), which was used to increase the viscosity of the solution. The dispersed LaOCl nanoparticles were characterized by X-ray diffraction found to be in a single LaOCl phase and their crystallite sizes were approximately 20 nm. The particle sizes of dispersed LaOCl nanoparticles were also observed to be approximately 20-30 nm by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Furthermore, dispersed LaOCl nanoparticles were confirmed to be modified with PEG-PAAc by an infrared spectra and improved dispersion stability in HEPES buffer by measuring solution turbidity. According to these results, we could successfully prepare PEG-modified 20-30 nm LaOCl nanoparticles well dispersed in HEPES buffer, which is useful for fluorescence bioimaging under NIR excitation.References[1] T. Konishi, M. Shimizu, Y. Kameyama and K. Soga., J. Mat. Sci: Mater. Electron., 18 (2007) S183.
9:00 PM - QQ3.12
Towards Radiolabeled G^C Module for Cellular Imaging of Bioactive Rosette Nanotubes.
Alaaeddin Alsbaiee 1 2 , Mustapha Jules 1 2 , Rachel Beingessner 1 2 , Hicham Fenniri 1 2
1 Chemistry, University of Alberta, Edmonton, Alberta, Canada, 2 , National Institute for Nanotechnology, Edmonton, Alberta, Canada
Show AbstractRosette nanotubes (RNTs) are biocompatible tubular architectures generated through the self-assembly of a DNA base hybrid motif. By utilizing the Watson-Crick H-bond acceptor-donor arrays of guanine and cytosine (G^C)(1), these motifs self-organize into hexameric rosettes, which then π-π stack to form the RNTs. The versatility of these architectures lies in their ability to have predefined chemical and physical properties for medical or biological applications, by covalently attaching the active functional groups to the ethylamine spacer on the G^C motif. In addition to their use in biomaterial interfaces, RNTs can be readily modified with a target number of therapeutic molecules, thereby acting as drug delivery vehicles for the treatment of diseases such as cancer and inflammatory disorders. In order to study and understand the pharmacological properties of the RNTs in more detail such as their rate of uptake in the cells and their distribution kinetics, it is important to obtain a radioactive RNT that can be monitored by scintigraphic techniques. The mercaptoacetyl triglycine (MAG3) motif, is a renal imaging agent which can form a complex with technetium-99m 99mTc or radiorhenium 186/188Re. The complex has sufficient in vivo stability that enables it to function as an effective radioimaging agent. In this study, we describe the synthesis of a twin-G^C base functionalized with the MAG3 motif and as proof of principle; we demonstrate its ability to complex non-radioactive rhenium and self-assemble into RNTs. 1 (a) Fenniri, H.; Deng, B. L.; Ribbe, A. E. J. Am. Chem. Soc. 2002, 124, 11064–11072. (b) Moralez, J. G.; Raez, J.; Yamazaki, T.; Motkuri, R. K.; Kovalenko, A.; Fenniri, H. J. Am. Chem. Soc. 2005, 127, 8307–8309.
9:00 PM - QQ3.13
A Facile Bottom-up Route to Self-assembled Biogenic Chitin Nanofibers.
Chao Zhong 1 , Ashleigh Cooper 1 , Adnan Kapetanovic 1 , Zhihua Fang 1 2 , Miqin Zhang 1 , Marco Rolandi 1
1 Materials science & engineering, University of Washington, Seattle, Washington, United States, 2 Materials Science and Engineering, Sichuan University, Sichuan China
Show AbstractChitin nanofibers, with their excellent stability and sturdy mechanical properties, are promising nanomaterials for regenerative medicine and tissue engineering. However, chitin nanofiber fabrication via self-assembly remains a daunting challenge due to chitin water insolubility. Here, we report the first in vitro self-assembly of ultrafine biogenic chitin nanofibers via two methods that involve simple chitin dissolution and precipitation in organic solvents. These two methods produce ultrafine nanofibers with controlled average diameters of 3 nm (hexafluoro 2-propanol) or 10 nm (LiCl/ N, N-dimethylacetamide). This facile bottom-up route in mild conditions solves the long-lasting deacetylation and degradation problems typically associated with conventional chitin nanofiber approaches. As indicated by proliferation studies with Schwann cells, these fibers are non-cytotoxic and can serve as scaffolds for tissue engineering.
9:00 PM - QQ3.14
Genetically Engineered Virus-based Platform for Simultaneous Second Window Near Infrared Fluorescence Imaging Using Single-walled Carbon Nanotubes and Efficient Chemotherapy of Cancer Cells.
Hyunjung Yi 1 2 , Debadyuti Ghosh 1 2 , Moon-Ho Ham 3 , Aditya Kohli 4 , Dong Soo Yun 1 , Woo-Jae Kim 3 , Michael Strano 3 , Angela Belcher 1 2 4
1 Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 4 Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractTheranostics, diagnostics combined with therapy, enables detection of tumors and monitoring of treatment of cancers. The intrinsic optical and electrical properties of nanomaterials, along with the ability to functionalize drug payloads and targeting moieties, make them attractive candidates for theranostic agents. Single-walled carbon nanotubes (SWNTs), rolled-up tubes of graphene sheets, show great promise for biological imaging and drug delivery due to their unique optical properties and ability to load drugs and targeting ligands. Especially, its band-gap fluorescence in the 2nd window near infrared (NIR) range (950 –1,600 nm) is advantageous to biological imaging because 2nd window NIR light has deeper penetration depth and lower auto-fluorescence background than visible and 1st window NIR light (700 -950 nm). For fluorescence imaging, SWNTs need to be non-covalently functionalized to retain its fluorescence. With non-covalent functionalization, however, it is challenging to effectively couple drugs and targeting ligands on small coating molecules while simultaneously maintaining the colloidal stability of SWNTs. Here we present a multifunctional virus-based approach to developing a theranostic agent for 2nd window NIR fluorescence imaging and drug delivery. M13 virus has five genetically modifiable capsid proteins positioned at different locations of the virus. Expression of material-specific peptides or targeting motifs on various proteins allows for genetic control and tunability of its function. To serve as a targeted imaging agent, genes for one of the minor coat proteins of the virus were modified to express cancer cell targeting ligands. Moreover, major coat proteins were genetically engineered to bind and disperse SWNTs in biological solutions through hydrophobic and π-π interaction between major coat proteins and SWNTs amplified with multivalent and cooperative binding. Moreover, native negative surface charge of M13 virus contributes colloidal stability of the virus-SWNT complex. To serve as a theranostic agent, chemotherapeutic agents, doxorubicin (DOX), were further chemically conjugated to the major coat proteins of the virus. Prostate cancer cells with various expression levels of the targeted biomarker were successfully imaged with the virus-SWNT complex using fluorescence in the 2nd window NIR range. Moreover, DOX delivered by the complex inhibited the cell growth at least 250 times more efficiently than free drugs and the inhibited growth was limited to the targeted cancer cells only while free drugs inhibited cell growth nonspecifically. These results demonstrate the multifunctional virus-based platform as a theranostic agent for 2nd window NIR fluorescence imaging and chemotherapy. We believe this approach can provide a new platform to utilizing SWNTs for fluorescence imaging and is potentially powerful due to the interchangeability of its components, permitting study of a wide array of cancers.
9:00 PM - QQ3.15
Mutations Alter Geometry and Mechanical Properties of Alzheimer’s Aβ(1-40) Amyloid Fibrils.
Raffaella Paparcone 1 , Matthew Pires 1 , Markus Buehler 1 2 3
1 Civil and Environmental Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Center for Computational Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractThe identification of more efficient therapies able to completely defeat a serious degenerative disease like Alzheimer’s is one of the main goals of drug discovery research. Realizing this ambitious goal requires a series of molecular insights that shed light on the crucial structural elements driving the stability, the elongation and toxicity of the Aβ(1-40) amyloid fibrils, which are directly related to this disease and are one of the most abundant species found in affected brain tissues. The stability of these fibrils depends on the highly ordered and dense network of hydrogen bonds, which is a general feature of the amlyoid configuration, and on the presence of a systematically repeated salt bridge, characteristic of the β-unit composing the fibril. Here we report the results of a series of molecular dynamics simulations of fibrils affected by local mutations addressing the disruption of the salt bridge stabilizing the main β-unit. We show that the salt bridge has a significant effect on the geometry, the stability and the mechanics of the Aβ peptides amyloids. We observe a decrease of the fibril periodicity—the period length—of ≈43.4%, and variations of the Young’s modulus of up to ≈153.6%. These results confirm that, while on the one hand the side chains are not involved in the formation of the β-strands composing the core of the amyloid structure, on the other, their presence, their size and interactions can be crucial in determining the properties of the fibers. Overall, side chains could be the key point to open new perspectives for the drug design and the definition of new therapies for Alzheimer’s disease, through the identification and subsequent chemical deactivation of the functional groups responsible of promoting the growth of the fibrils, ensuring their stability and determining their further aggregation in amyloid plaques.
9:00 PM - QQ3.16
Use of Disulfide-PEG ligands to Synthesize 1 - 130 nm Gold Nanoparticles with High Stability in Aqueous Phase.
Eunkeu Oh 1 , Kimihiro Susumu 1 , Hedi Mattoussi 2 , Alan Huston 1
1 Optical Science, Naval Research Laboratory, Washington, District of Columbia, United States, 2 Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, United States
Show AbstractWe have previously reported the use of poly(ethylene glycol) (PEG550 or 750)-appended disulfide bidentate ligands to develop a one phase synthetic method for preparing water-soluble 1-20 nm Au nanoparticles (AuNPs). One of the key aspects of this method is controlling the ratio of bidentate ligand to Au. The prepared AuNPs exhibited remarkable stability in the presence of high salt concentrations, over a wide range of pHs and in the presence of strong competition from dithiothreitol. In addition, we showed that this route could allow for the in situ functionalization of the NP surface with the desired functional groups. Here we build on those findings and show that a combination of temperature treatments and successive “small” injections of additional Au precursors can further expand the size range of spherical nanoparticles up to 130 nm. These steps have removed bottlenecking in the NP growth (experienced in the single step injection at room temperature) and allowed control over the amount of Au- ligand precursors introduced stepwise at each injection. These large size NPs benefit from the strong affinity of the PEG appended disulfide ligands, facilitating the preparation of surface-functionalized and stable AuNPs without the need for ligand exchange with citrate-stabilized large AuNPs. We will describe the synthetic procedure and optical and structural characterization of the nanocrystals using UV-vis spectroscopy, dynamic light scattering, high resolution transmission and scanning electron microscopy (TEM and SEM).
9:00 PM - QQ3.18
Time-resolved Structural Evolution of Mesoporous Silica Nanoparticles.
Teeraporn Suteewong 1 , Hiroaki Sai 1 , Roy Cohen 2 , Barbara Baird 2 , Suntao Wang 3 , Michelle Bradbury 4 , Sol Gruner 3 , Ulrich Wiesner 1
1 Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 2 Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States, 3 Physics, Cornell University, Ithaca, New York, United States, 4 Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York, United States
Show AbstractDue to their large accessible porosity and tunable surface functionalities, mesoporous silica nanoparticles (MSNs) with ordered nanoporous structures have attracted interest from the biomedical research community as a well-defined nanoscale platform for biological imaging, sensing and drug delivery. In this study, we tracked the morphological evolution of MSNs synthesized from a cationic surfactant and organosilane precursors by small-angle X-ray scattering (SAXS) as well as transmission electron microscopy (TEM). By tuning the chemical compositions of the starting solution, we investigated the role of each species for structure formation. Time-resolved SAXS studies have revealed the growth kinetics of these MSNs.
9:00 PM - QQ3.19
Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure.
Teeraporn Suteewong 1 , Hiroaki Sai 1 , Roy Cohen 2 , Suntao Wang 3 , Michelle Bradbury 4 , Barbara Baird 2 , Sol Gruner 3 5 , Ulrich Wiesner 1
1 Department of Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 2 Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States, 3 Department of Physics, Cornell University, Ithaca, New York, United States, 4 Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York, United States, 5 Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York, United States
Show AbstractNanoparticles have been used for applications in biomedical imaging, sensing and drug delivery. Besides suitable surface and colloidal properties, nanoparticle architecture and composition are key to the achievable property profiles. Ordered mesoporous silica nanoparticles in particular have attracted considerable interest in aforementioned applications as they provides high surface area and large pore volume, while maintaining the intrinsic properties of silica. Mesoporous silica with three-dimensional pore systems, provide advantages in diffusion and transport over one-dimensional channel systems such as MCM-41 materials. Cubic mesoporous silica possessing a cage-type structure that is three-dimensionally interconnected with small open windows is a promising material, e.g. as a carrier for biological molecules. In this work, we present the room temperature synthesis of cubic mesoporous silica nanoparticles. Transmission electron microscopy (TEM) and small-angle x-ray scattering (SAXS) will be used to thoroughly characterize structural aspects of the materials. N2 sorption measurement will be discussed to characterize surface area and pore size distribution of the nanoparticles. From additional experiments we will describe the synthesis of cubic mesoporous silica nanoparticles with variations in pore and particle size. Fluorescent nanoparticle variants will be discussed in the context of cellular uptake.
9:00 PM - QQ3.2
Continuous Microflow Synthesis of InP Quantum Dots in Supercritical Octane.
Jinyoung Baek 1 , Peter Allen 2 , Moungi Bawendi 2 , Klavs Jensen 1
1 Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractInP quantum dots (QDs) are of technological interest for visible-light applications in optoelectronic devices and bio-imaging process as the replacement of CdSe QDs. However, current InP QD syntheses have not been produced QDs with narrow size distributions when compared to CdSe QDs. We have utilized a high temperature and pressure microfluidic system to enable the utilization of a wide variety of solvents which have not been traditionally accessible in QD synthesis, such as supercritical octane. In addition, the microfluidic system provides precise control of synthetic conditions to enable fast screening of growth conditions. This work explores the use of a 2 stage high temperature and pressure microreactor system. By separating the mixing process in the first reactor, from the ripening process in the second reactor, we have found that InP QD syntheses are primarily dominated by interparticle ripening. Using the microreactor we have probed the effects of solvent viscosity, temperature, particle concentrations, and indium to fatty acid ratio. By operating the microfluidic reactors above 320 C with supercritical octane as a solvent, high quality InP QDs were obtained in as little as 1.5 minutes. We have found that adjusting the indium to fatty ratio has largest effect on particle size due to enhanced interparticle ripening. Using this microreactor system we are able to access InP QDs spanning the visible region.
9:00 PM - QQ3.20
Synthesis and Crystal Growth of Iron Oxide Nanoparticles for Drug Delivery Applications.
Vijaya Rangari 1 , Arifa Perveen 1 , Shaik Jeelani 1
1 Materials Science and Engineering, Tuskegee University, Tuskegee, Alabama, United States
Show AbstractAbstract: Superparamagnetic and monodispersed iron oxide nanoparticles with porous structures have been successfully synthesized using a template-free solvothermal and sonochemical routes. In present work, we report the versatile synthesis procedures for drug carriers. The iron oxide nanoparticles were initially synthesized by ultrasound irradiation of ironpentacarbonyl, Deccalene, PVA and water for 3 hrs. These nanoparticles were characterized by X-ray diffraction and found to be highly crystalline magnetite (Fe3O4) nanoparticles. These as-prepared magnetite nanoparticles were further used as a seeds to grow the larger porous iron oxide crystals. The crystal growth was carried out by reacting the iron(II) acetate, Ethylenedyamine, HMT, distilled water and as-prepared magnetite nanoparticles at 900C for 2 hrs. These nanoparticles were further characterized by X-ray diffraction, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). X-ray and TEM results suggest that the as-prepared and crystal grown particles are crystalline. The particles sizes measured are ~5-10nm and 100nm respectively for as-prepared and grown crystals. The crystal grown iron magnetite particles were also found to be highly porous and they can be efficiently used for larger amounts of therapeutic drug carries and targeted drug delivery application.
9:00 PM - QQ3.21
Synthesis of Biodegradable Nanoparticles Using a Novel Electrospray Process.
Begona Almeria 1 , Tarek Fahmy 2 3 , Alessandro Gomez 1
1 Mechanical Engineering, Yale University, New Haven, Connecticut, United States, 2 Biomedical Engineering, Yale University, New Haven, Connecticut, United States, 3 Chemical Engineering, Yale University, New Haven, Connecticut, United States
Show AbstractA multiplexed electrospray (ES) system is presented for the synthesis of nanoparticles for drug delivery. The particles consist of a matrix of a biodegradable polymer, PLGA, encapsulating an active agent, Doxorubicin. They are synthesized by ES drying, that is, the particles are the solid relics left over after solvent evaporation from the parent electrospray droplets. For a given polymer/solvent combination, once electrical conductivity and evaporation rate are known, the size of the particles can be easily selected. Particles with diameters as small as 25nm were synthesized with this approach, a size that is not within reach of the well-developed synthesis alternative based also on solvent evaporation technique but without ES dispersion. The synthesis approach is easy to scale-up using microfabricated, multiplexed arrays consisting of several electrospray nozzles operating in parallel. The technique is also compatible with coatings with emulsifiers or ligands for targeted drug delivery. Results will be presented on the size and morphology of the synthesized particles via SEM/TEM analysis, and on the drug release rate using fluorescence emission from the active agent.
9:00 PM - QQ3.22
Polyol-made Zn0.8Mn0.2S Nanoparticles as Potential Bimodal, Luminescent and Magnetic, Imaging Probes: from the Synthesis to the Toxicity Effects.
Meriem Gaceur 1 , Michel Boissiere 2 , Joachim Allouche 3 , Miriana Hamadi 1 , Marion Giraud 1 , Souad Ammar 1
1 ITODYS UMR-CNRS 7086, Paris Diderot University, Paris France, 2 ERRMECe EA1391, Cergy-Pontoise University, Pantoise France, 3 IPREM/ECP UMR-CNRS 5254 , Pau et des Pays de l’Adou University, Pau France
Show AbstractRecently, many researchers have investigated the different properties of Zn1-xMnxS nanoparticles which combine both magnetic and optical properties. Such nanocrystals open a wide area of application in biomedicine with the real opportunity to use them as efficient both magnetic and luminescent imaging probes.We present here, the synthesis of highly crystalline monodisperse nanoparticles of Zn1-xMnxS of about 2 nm in size, obtained by the well known polyol process, within a solubility limit in the blende lattice of x = 0.3. A hydrophilic ligand, namely mercapto-acetic acid, was then anchored at the surface of the as-produced particles to form stable colloids in water. The optical properties were characterized by UV-visible absorption and emission spectroscopies on the colloids while the magnetic properties were characterized by dc-magnetometry on the powders. The studied magnetically diluted semiconductors exhibit a strong emission in the visible and a Curie-Weiss paramagnetic behavior. The combination of these magnetic and optical features in such systems makes them very promising as potential positive contrast agents for the nuclear magnetic resonance imaging (MRI) and luminescent inorganic dyes.Furthermore, DNA fragmentation and cytotoxicity caused by these particles were evaluated on chinese hamster ovarian (CHO-K1) cells with various doses for 24h. DNA strand breakage was detected by single-cell microgel electrophoresis (comet) assay. Cytotoxic effects were analyzed by trypan blue exclusion test and Alamar Blue reduction.The trypan blue exclusion test and the Alamar Blue reduction assay did not show any loss of cell viability and no modification in the cell morphology is observed. In the comet assay, there was no evidence of increased DNA damage for QDs.These results are very encouraging for future biomedical in vivo applications
9:00 PM - QQ3.23
Multifunctional Hydroxyapatite/gold Nanostructures for Therapy and Diagnosis.
Maria Elisabete Costa 1 , Catarina Santos 1 2 , Maria Margarida Almeida 1
1 Department of Ceramic and Glass Engineering, CICECO, University of Aveiro, Aveiro Portugal, 2 Polytechnical Institute of Setubal, EST, Setubal Portugal
Show AbstractStrong expectations are focused on the increasingly sophistication of nanosized materials and chemical assemblies for improving the 21st century healthcares. This includes superior diagnostics and biosensors, improved imaging techniques, innovative therapeutics and tissue regeneration and repair technologies. Such demanding goals require the development of multifunctional systems built of nanostructured multiphase materials that achieve the desired properties by combining different features from dissimilar materials. Calcium phosphate (CP) are unquestionable biomaterials for bone repair, osteologic implant coating, cements and scaffolds. Moreover the possibilities of tailoring CP particle size and shape at a nanoscale may be exploited for novel drug delivery systems (DDS) displaying a controlled behaviour towards uptake, clearance, degradation, non-targeted accumulation, and phagocytosis prior to the therapeutic payload deliver. On the side of diagnosis and therapeutics novel techniques including photothermal imaging and therapy are now being addressed. They rely on noble metal nanostructures displaying surface Plasmon effect which have a high potential for anticancer thermal therapy and diagnosis (imaging) as recently demonstrated. The coupling of CP nanoparticles with a noble metal nanostructure may thus impart multifunctinality to a DDS. This approach was followed in the present work which reports the synthesis of a nanostructured system composed by hydroxyapatite (HAP) nanosized particles on which surfaces gold nanoparticles are locally precipitated. HAP nanoparticles are firstly precipitated by hydrothermal method at high temperature (T>100○C). The obtained HAP nanoparticles are then exposed to a gold precursor solution from which gold cations are driven to HAP particles surfaces where they locally precipitate as metallic gold. Experimental techniques (XRD, TEM, and UV) show that metallic gold nanosized precipitates with an average size of 5nm are obtained under highly controlled conditions. The roles of the relevant experimental variables including reagent type and concentrations, pH, and temperature are discussed in the framework of gold nucleation and growth mechanisms.
9:00 PM - QQ3.24
The Effects of Heat Treatment on the NiO Nanoparticles.
Dong Yun Han 1 , Hongyan Wang 2
1 , Liaoning Shihua University, Fushun China, 2 , Fushun Vocational Technology Institute, Fushun China
Show AbstractThe microemulsion method is one of the effective methods for preparing nanoparticles in recent years. It has the advantages of simple apparatus, easy operation and controllable particle size. The precursors of NiO nanoparticles were successfully prepared in TritonX-100/n-hexanol/cyclohexane/water W/O microemulsion system using nickel chloride and ammonia water as raw materials. NiO nanoparticles were obtained after heat treatment of the precursors. The effects of heat treatment on the morphology and size distribution of NiO nanoparticles were systematically investigated. The result showed that the size, morphology and dispersion of NiO nanoparticles in the microemulsion state were much better than that in the state after heat treatment. XRD and TEM also showed the size of the NiO nanoparticles increased largely with the increase of heat treatment temperature.
9:00 PM - QQ3.26
Study of the Fluorescence Enhancement of Sulforhodamine B Acid Chloride Produced by Au Nanoparticles.
Marcin Grzelczak 1 , Andres Guerrero-Martinez 1 , Isabel Pastoriza-Santos 1 , Jorge Perez-Juste 1 , Luis M. Liz-Marzan 1
1 Physical Chemistry, Unidad asociada CSIC-Universidade de Vigo, Vigo Spain
Show AbstractThe widesspread popularity of the fluorescence-based detection in bioscience has contributed in the last decade to the development of new methods which increase the detection sensitivity. It has been discovered that metal nanoparticles can act as antennae that enhance the luminescence of fluorophores (by 10-fold or more) when they are in close proximity to the metal nanoparticle surface.1 Although this enhancement mechanism is not well understood, it is known that metal nanoparticles can influence luminescence in several ways: a) enhancing the molecule optical absorption through near field enhancement, b) modifying the molecule radiative decay rate, and c) incresing the coupling efficiency of the fluorescence emission to far field detection via nanoparticle scattering. In all cases, the enhancement factor is highly dependent on the fluorophore-metal distance, as well as on the nanoparticle metallic nature, size and shape. It is known that Au nanoparticles can produce intense enhancements of the fluorescence, but a systematic study of the optimum conditions, in terms of fluorophore-nanoparticles distance, is still needed.Herein, we present a study of the effect of the fluorophore-metal nanoparticle distance on the enhanced flourescence displayed by sulforhodamine B acid chloride (SR), in close proximity to 60 nm Au nanoparticles. The spacing between the SR and the Au nanoparticles is controlled by a silica shell. Using the protocol recently developed by our group, different batches of Au nanoparticles coated with silica shells of various thickness were prepared to vary the SR-Au nanoparticle distance. Additionally, to avoid molecular diffusion through the silica shell, dye molecules with active sulfonyl chloride groups were covalently linked to the silica surface using a previous amine surface functionalization step of the core-shell nanoparticle.1 J.R. Lakowicz, Anal. Biochem. 2005, 337, 171-194. W. L. Barnes, J. Of Modern Optics 1998, 45, 661-699.2 C. Fernández-López, C. Mateo-Mateo, R.A. Alvarez-Puebla, J. Pérez-Juste, I. Pastoriza-Santos, L.M. Liz-Marzán, Langmuir 2009, 25, 13894-13899.
9:00 PM - QQ3.27
Newkome Type Dendron-gold Conjugates: Syntheses, Stability, and Effect of Core Size.
Tae Joon Cho 1 , Rebecca Zangmeister 1 , Robert MacCuspie 1 , Anil Patri 2 , Vincent Hackley 1
1 , National Institute of Standards and Technology , Gaithersburg, Maryland, United States, 2 , Nanotechnology Characterization Laboratory, SAIC Frederick, Inc., National Cancer Institute , Frederick, Maryland, United States
Show AbstractFour modified newkome type dendrons were synthesized to yield gold-dendron conjugates. Dendrons were designed with consideration of the sulfide content, generation number, steric effects that would inhibit reaction and impact conformation, hydrophilicity of the dendron, and surface functionality of the termini. The dendrons are disulfide bis first generation carboxyl terminated (G1-COOH), disulfide bis second generation carboxyl terminated (G2-COOH), monosulfhydryl first generation carboxyl terminated (SH-G1-COOH), and thioctic acid first generation carboxyl terminated (TA-G1-COOH). G1- and G2-COOH are bi-directional dendrons that have cystamine cores containing a disulfide group. SH-G1-COOH was prepared by treatment of G1-COOH with dithioerythritol to yield a pair of molecules each with a free thiol group by cleaving the disulfide bond. TA-G1-COOH has a thioctic acid moiety, which is a 5-membered ring containing a disulfide group, to provide two anchoring thiols per dendron to react with the gold surface. Chemical structures were confirmed by 1H and 13C NMR and MALDI-TOF mass spectrometry. 10 nm gold-dendron conjugates were prepared and purified by stirred cell ultrafiltration. Particle size and surface plasmon resonance of the conjugates were characterized by dynamic light scattering (DLS) and UV-Vis spectroscopy, respectively. X-ray photoelectron spectroscopy (XPS) measurements showed different S/Au ratios on the gold-dentron nanoparticles, induced by steric effects to the conjugation reaction or the conformation of Au-dendron conjugates, depending on the chemical structures of the dendrons. The colloidal and chemical stability of the conjugates as a function of temperature, pH, and suspending medium such as physiological saline levels (PBS buffer), and with respect to chemical resistance toward KCN, was investigated using DLS and UV-Vis absorption. Additionally, core size dependent properties of gold-dendron conjugates, which were prepared by conjugation of TA-G1-COOH to various gold colloids (5, 20, 30, and 60 nm, nominal diameters), and their stability were evaluated by DLS, UV-Vis, and XPS.
9:00 PM - QQ3.28
Robust, Facile Methods for Synthesizing Nanoparticles Densely Functionalized with Oligonucleotides.
Joshua Cutler 1 , Ke Zhang 1 , Dan Zheng 1 , Chad Mirkin* 1
1 Chemistry, Northwestern University, Evanston, Illinois, United States
Show AbstractBiomolecule-functionalized nanoparticles are beginning to substantially impact the way that diseases are diagnosed and treated due to a number of unique and advantageous properties. In particular, when oligonucleotides are densely arranged on a nanoparticle surface, many new behaviors emerge including elevated and narrow melting transitions, enhanced binding to targets, high cellular uptake without transfection agents, dramatic nuclease resistance and robust RNAi engagement. Previously, our group and others have used gold nanoparticles (AuNPs) as scaffolds to synthesize these constructs due to properties that set AuNPs apart from other colloids such as their facile aqueous synthesis, dense surface-ligand assembly and strong absorption/scattering properties. However, significant advances could be obtained by using different core materials with unique physical properties. Herein, we present novel methods to prepare high density DNA nanostructures and demonstrate that many of the emergent properties associated with the polyvalent DNA-gold nanoparticle conjugate are independent of the nanostructures’ core composition.
9:00 PM - QQ3.29
Oligonucleotide – Nanoparticles Conjugates.
Valerie Gerard 1 , Damian Aherne 1 , Nicolas Spinelli 2 , Eric Defrancq 2 , Yurii Gun'ko 1
1 Chemistry, Trinity College Dublin, Dublin Ireland, 2 Département de Chimie Moléculaire-UMR CNRS 5250, Université J. Fourier, Grenoble France
Show AbstractMetal nanoparticles have raised much interest in recent years due to their unique optical and electronic properties. Functionalising their surface with biomolecules has lead the way to the formation of controlled assemblies[1] which have found applications in fields as various as biosensing[2], drug delivery[3] and SERRS[4]. Most of this research however has focused on conjugation and assembly of spherical nanoparticles[5] even though more highly shaped entities have exhibited some interesting size- and shape-dependent properties[6]. A recently developed method to produce size-controlled silver nanoprisms rapidly and at room temperature[7] opened the way to new nanostructures using these silver nanoprisms as templates[8]. We believe that the functionalisation of such anisotropic materials has a range of potential applications in photonics and biomedicine.The aim of our work is thus to conjugate oligonucleotides to anisotropic metallicnanostructures (such as nanoprisms, nanorings or nanoboxes) and quantum dots (e.g. CdTe nanoparticles) and to investigate the properties of the resulting systems. A range of Au/Ag and QD conjugates with oligonucleotides bearing a T6 phosphorothiate at 3'end and a amino function at 5'-end (5’ NH2 - A10 TAG GAA TAG TTA TCA(T6) 3’ and 5’ NH2 – A10 TGA TAA CTA TTC CTA(T6) 3’) have been prepared. The characterisation of new nanoconjugates involved a wide range of techniques including absorption spectroscopy, circular dichroism, gel electrophoresis and electron microscopy. The new nanoconjugates demonstrated very interesting optical and sensing properties. These materials might find a range of potential applications in photonic and plasmonic devices and biotechnology.References:[1]R. C. Mucic, J. J. Storhoff, C. A. Mirkin, R. L. Letsinger, Journal of the American Chemical Society 1998, 120, 12674-12675.[2]J. J. Storhoff, R. Elghanian, C. A. Mirkin, R. C. Mucic, R. L. Letsinger, Vol. 120, Journal of the American Chemical Society, 1998, pp. 1959-1964.[3]K. Hamad-Schifferli, J. J. Schwartz, A. T. Santos, S. Zhang, J. M. Jacobson, Nature 2002, 415, 152-155.[4]F. McKenzie, D. Graham, Chemical Communications 2009, 5757-5759.[5]M. Fischler, U. Simon, Journal of Materials Chemistry 2009, 19, 1518-1523.[6]M. Hanauer, S. Pierrat, I. Zins, A. Lotz, C. Sonnichsen, Nano Letters 2007, 7, 2881-2885.[7]D. Aherne, D. M. Ledwith, M. Gara, J. M. Kelly, Advanced Functional Materials 2008, 18, 2005-2016.[8]D. Aherne, D. E. Charles, M. E. Brennan-Fournet, J. M. Kelly, Y. K. Gun'ko, Langmuir 2009, 25, 10165-10173; D. Aherne, M. Gara, J. M. Kelly, Y. K. Gun'ko, Advanced Functional Materials, 20, 1329-1338.
9:00 PM - QQ3.3
Stability Investigations of CuInS2 Based Heavy-metal Free Nanoparticles.
Chuang Xie 1 2 4 , Yu Zhang 3 2 , Andrew Wang 4 , William Yu 4 , Jingkang Wang 1 , Jian Xu 2
1 School of Chemical Engineering and Technology, Tianjin University, Tianjin China, 2 Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States, 4 , OceanNanoTech LLC, Springdale, Arkansas, United States, 3 College of Electronic Science and Engineering, Jilin University, Jilin, Jilin Province, China
Show AbstractCuInS2, a well known and important photovoltaic material[1], also has perspective application in biomedical labeling[2]. Due to the toxicity and environment considerations, CuInS2 nanocrystals take big advantages of Cd and Pb based nanocrystals although they were well developed and have appealing optical properties. Recent progresses suggest CuInS2 based heavy metal free nanoparticles, such as ZnCuInS and CuInS2/ZnS core/shell nanoparticles, are good enough and have been applied to in vivo biological labeling within visible and NIR windows[3]. However, little has been done to test the stability of the PL property of CuInS2 based nanoparticles which is very important to the biomedical applications.In the present work ZnCuInS/ZnSe/ZnS core/shell nanoparticles were synthesized of which the PL ranged from green (555nm) to red (620nm) by varying the composition and the size of the core. In consideration of the effect of structure, CuInS2/ZnS core/shell nanoparticles with no zinc in the core were also prepared. The shells growth was adjusted to investigate the effect of the shell thickness on the stability of nanoparticles. The effect of nanoparticles was also considered by test 3 different concentrations of each nanoparticle. Commercial CdSe/ZnS core/shell nanoparticles were used as reference to compare to the stabilities of CuInS2 based nanoparticles. All the stability tests were executed under the same condition of ultrahigh intensity (26mW/cm2) of UV light radiation in air at room temperature.Expected decays of the PL intensity occurred while the samples of different concentrations show different decay trajectories. The half-life time prolonged to 3 and 5 times when the concentration increased to 5 and 10 times. This is reasonable since the average radiation on each nanoparticle decreased. It was found the thickness of the shell dramatically influence the stability of the nanoparticles. 1nm of additional shell could make the half-life time twice of that before additional shell growth. Interestingly, a recovery of the PL intensity of the nanoparticles was observed after being store in the darkness overnight. This recovery of CuInS2/ZnS was much more than that of ZnCuInS/ZnSe/ZnS and could be up to ~10% of the initial. Comparing to commercial CdSe/ZnS nanoparticles, of which the half-life time is less than 3h under the ultrahigh intensity of UV radiation, the CuInS2 based nanoparticles we made showed up to 15h of half-life time under the same condition and indicated a very strong stability. This is respectably useful for the application in biomedical fields.[1] T. Yamaguchi, Advanced Materials in Electronics, 229 (2004).[2] H. Nakamura, W. Kato, M. Uehara, K. Nose, T. Omata, S. Otsuka-Yao-Matsuo, M. Miyazaki, H. Maeda, Chemistry of Materials 18, 3330 (2006).[3] L. Li, T. J. Daou, I. Texier, T. T. Kim Chi, N. Q. Liem, P. Reiss, Chemistry of Materials 21, 2422 (2009).
9:00 PM - QQ3.30
Synthesis OF β-Cyclodextrin-PEG-Folic Acid for Delivery of Antitumor Phytosterol.
Olatunji Abimbola 1 2 , Godwin Ananaba 1 2 , Ishrat Khan 1 2
1 Chemistry, Clark Atlanta University, Atlanta, Georgia, United States, 2 Center for Functional Nanoscale Materials (CFNM), Clark Atlanta University, Atlanta, Georgia, United States
Show AbstractAn inclusion complex of β-cyclodextrin with hydrophobic compounds has been confirmed by other groups. Studies have shown that when conjugated with site directed moieties, these inclusion complexes can be used in drug delivery. In this study, we synthesized and characterized a β-cyclodextrin -PEG-Folic Acid (β-CD-PEG-FA) bio-conjugate for antitumor delivery of phytosterols. Phytosterols are plant sterols that have been well documented to reduce tumor cell growth and migration. We hypothesize that the β-CD-PEG-FA will facilitate better phytosterol absorption and increase β-cyclodextrin solubility. Since most tumor cells over-express folic acid, inclusion of folic acid in the construct will direct phytosterols to tumor sites. To investigate the above hypothesis, phytosterols were supplemented with β-cyclodextrin to form an inclusion complex. The complex was characterized by IR, NMR and DSC analysis. IR studies of the inclusion complex and Physical mixture revealed changes in the characteristic peaks of the inclusion complex suggestive of the formation of a new compound. H1NMR studies reveal a downfield resonance shift of β-CD protons as the concentration of Phytosterol is increased, while leaving β-CD concentration constant. NOESY NMR studies suggest that most of phytosterol moieties were encapsulated in the β -CD cavity, as evidenced by cross peaks between phytosterol and the hydrogens inside β-CD’s cavity. β-CD-PEG-FA was synthesized through β-CD TOSYLation, PEGylation, and conjugation to Folic. Work in progress involves RNA isolation of PC3 cells supplemented with Phytosterol included β-CD-PEG-FA. Isolated RNA will be converted to DNA, followed by PCR and Gel electrophoresis to look for specific genes expressed in the presence of Phytosterol.
9:00 PM - QQ3.31
Design and Synthesis of Stimuli-Sensitive Micelles that Can Unveil Shielded Targeting Ligands.
Raghunath Roy 1 , Millicent Sullivan 1 , Thomas Epps 1
1 Chemical engineering, University of Delaware, Newark, Delaware, United States
Show AbstractDrug carriers designed from amphiphilic block copolymers are of great importance as they readily form self-assembled nano-structures such as micelles and vesicles that can encapsulate various therapeutic agents. However, for these polymeric vehicles to realize their full potential in systemic delivery, it is important to design them to target the desired organ, tissue, or cell type. Targeted delivery is commonly accomplished by decorating the corona (surface) of the delivery vehicle with the appropriate peptide or aptamer-based ligands. This approach often shows excellent in vitro effectiveness, but fails when applied in vivo. We hypothesize that a fully exposed ligand will have non-specific interactions with numerous biomolecules during its transport, leading to shortened carrier half-life in the blood circulation or degradation of the ligand. Thus, we present the design, synthesis and study of a unique block copolymer micelle based targeted drug delivery vehicle that will circumvent these issues. Our custom designed block copolymer is based on poly-methylmethacrylate (PMMA) and polyethylene glycol (PEG) with an UV cleavable o-Nitrobenzyl alcohol in between the two blocks. A model peptide ligand (RGD) is covalently incorporated into the hydrophilic PEG block to be shielded from non-specific interactions. The RGD peptide then connects PMMA and PEG through a peptide sequence that will selectively be cleaved by model enzyme chymotrypsin to unveil the RGD to the surface of the micelle. This fundamental strategy can easily be extended to incorporate well-known cell penetrating peptides that can facilitate cellular entry, and disease-relevant peptide sequences that would be cleaved by a selective enzyme
9:00 PM - QQ3.32
Artificial Eumelanin Nanoparticles with Excellent Dispersibility for Radical Scavenging Effect.
Kuk-Youn Ju 1 , Jin-Kyu Lee 1
1 Chemistry, Seoul National University, Seoul Korea (the Republic of)
Show AbstractA novel synthetic method was developed to prepare size-controllable eumelanin nanoparticles with excellent water dispersibility; eumelanins are well known bio-polymers that are widely distributed in many parts of living organisms exhibiting many interesting properties and various biological functions. Eumelanin nanoparticles were synthesized with size control through neutralization of dopamine hydrochloride with NaOH followed by spontaneous air oxidation of dopamine. Although the particle characteristic of natural melanins was understood to be significantly affected by the biological and structural environment, eumelanin nanoparticles can be realized through the chemical reactions only. Furthermore, eumelanin nanoparticles are smaller than 100 nm showed excellent dispersion stability in water and surface modified eumelanin nanoparticles could be stable in biological medium such as buffer solution and serum as well, which is essential for use in many related biological investigations. Details on synthesis and characterization of artificial eumelanins and their interesting feature of radical scavenging activity will be discussed.
9:00 PM - QQ3.33
Silica-coated Nanophosphors.
Georgios Sotiriou 1 , Melanie Schneider 1 , Sotiris Pratsinis 1
1 ETH Zurich, Particle Technology Laboratory, Zurich Switzerland
Show AbstractNanophosphors are a promising new class of inorganic labels for bio-imaging applications, possessing a narrow emission bandwith, good photostability and low toxicity. Additionally, silica coating of nanoparticles enhances the dispersibility, bio-compatibility and the surface functionalization properties demonstrably. Combining these excellent properties in silica coated core-shell nanophosphors could lead to the replacement of disadvantageous existing bio-imaging probes such as organic dyes (photobleaching) and quantum dots (blinking, toxicity).In this study, pure and silica coated Y2O3:Tb3+ nanophosphors were synthesized by flame spray pyrolysis. The produced particles consisted of the monoclinic crystal phase and showed bright green phosphorescence. By conducting an annealing study of the silica coated, as well as the uncoated samples, modifications in size and crystallinity could be observed. While the coated samples showed a general enhancement in crystallinity, the uncoated crystals expressed a phase transition from the monoclinic to the cubic crystal phase and an increase in crystal size. Analyzing the luminescent properties of these particles, a higher light output could be detected in case of the monoclinic Y2O3:Tb3+. Consequently, in terms of Tb3+ phosphorescence in an Y2O3 host matrix, the monoclinic crystal phase can be considered superior to the cubic phase.
9:00 PM - QQ3.34
Color Tunable Nanophosphors.
Georgios Sotiriou 1 , Melanie Schneider 1 , Sotiris Pratsinis 1
1 ETH Zurich, Particle Technology Laboratory, Zurich Switzerland
Show AbstractBiological labels are used in bio-imaging and the ability to tag cells and biomolecules facilitates diagnosis and therapy. Even though organic dyes are used for such applications, their photobleaching inhibits their further employment. Quantum dots do not exhibit photobleaching and their emission color can be tuned by their size, however, their optical blinking and the high toxicity of their components restrict their use in bio-applications. An alternative strategy for such biolabeling applications are inorganic nanoparticles consisting of a host crystal matrix doped with lanthanide ions, the so-called nanophosphors. The color of these particles depends on the doping ion and not on their size, while their optical properties are superior to organic dyes and quantum dots. The target of this project is the flame synthesis of Y2O3 nanoparticles doped with Tb3+ and Eu3+. The co-doping of these ions in the Y2O3 matrix allows for the fine color tuning of the emission bandwidth.
9:00 PM - QQ3.35
Facile Synthesis of Lanthanide Core-shell Nanoparticles with Simultaneous Enhancement in Paramagnetic and Upconversion Properties.
Zhengquan Li 1 , Zeye Wang 1 , Liming Wang 1
1 Department of Materials Physics, Zhejiang Normal University, Jinhua, Zhejiang, China
Show AbstractLanthanide nanocrystals which exhibit sharp fluorescent emission with high quantum efficiency and long life-time have been widely used as fluorescent bioprobes in biomedical research. Moreover, many lanthanide ions doped in nanocrystals such as Gd3+ possessing a large number of unpaired electrons, can efficiently alter the relaxation of surrounding water protons and have been popularly employed as contrast agents in magnetic resonance imaging (MRI). Therefore, rational design of lanthanide nanostructures having different functions within a single nanocrystal will support for the development of a multifunctional nanoplatform for enhancing diagnostic and therapeutic power. We have developed a seed-mediated synthetic method to prepare bi-functional lanthanide nanocrystals with a core-shell structured geometry, which could simultaneously enhance both paramagnetic property and upconversion fluorescence of the nanocrystals compared to their individual nanocrystal counterparts. By using upconversion nanocrystals (such as NaYF4:Yb,Er) as seeds, a paramagnetic shell (such as NaGdF4) could be epitaxially grown on their surface. Coating a solid compound shell on a luminescent nanocrystal is able to eliminate the surface defects of the luminescent nanocrystals and thus enhance their fluorescence property. At the same time, paramagnetic lanthanide ions locating closely to the surface have a better chance to efficiently exchange with the surrounding water protons than those doped evenly inside the whole nanocrystal, thereby improving their MR relaxivities. These nanocrystals are uniform in size, stable in water and easy for conjugation after surface-modification with a silica layer. They may serve as a versatile imaging tool with duo capabilities of MRI and fluorescence imaging for future biomedical application.
9:00 PM - QQ3.36
Synthesis of Carbon-coated Upconversion Nanocrystals as Biocompatible and Fast Cell-imaging Probes.
Zhengquan Li 1 , Xinghui Liu 1 , Liming Wang 1
1 Department of Materials Physics, Zhejiang Normal University, Jinhua, Zhejiang, China
Show AbstractAmong various fluorescent bioprobes, lanthanide-doped near infrared (NIR)-to-visible upconversion nanocrystals (UCNs), which can convert NIR lights to visible lights, are of particular interest. Since most biological species absorb minimally in the NIR window, their use in fluorescent imaging will minimize the extent of auto-fluorescence and photo-damage induced, as well as enable high penetration depth of light in tissues. These UCNs also show superior photo-stability and can serve as efficient electron donors in FRET detection, owing to the fact that lanthanide ions are doped inside nanocrystals matrix and exhibit sharp emissions with long lifetime. Since most of high-quality upconversion nanocrystals were prepared inside organic solvents and bear a hydrophobic surface, surface-modification of these UCNs is crucial to make them useful for various biological applications. Unfortunately, the current methods available to achieve a desirable surface exhibiting both high luminescence and well biocompatibility are limited. We have developed a facile microemulsion route to synthesize hydrophilic core-shell structured NaYF4@C nanoparticles through carbonizing glucose on hydrophobic NaYF4 nanocrystals. Owing to the particular amphiphilic structure of carbon materials, carbonized-glucose on these UCNs is not only able to preserve strong fluorescence from the core upconversion nanocrystals, but it also confers good water-solubility and bears various function groups for conjugating to biomolecules. In particular, these carbon-coated nanocrystals possess a better cell biocompatibility and can be rapidly internalized into cells, when compared to 10 nm silica-coated UCNs, a commonly used hydrophilic UCNs in many biological applications. Such unique features of carbon-coated UCNs may find promising applications in imaging, diagnosis and therapy purpose. This facile surface-modification route also has the potential to be extended to a broad range of other hydrophobic nanocrystals.
9:00 PM - QQ3.4
A Modular Phase Transfer and Ligand Exchange Protocol for Quantum Dots.
Jennifer Amey 1 , Nathanial Miska 1 , Hyunjoo Han 1 , Joshua Zylstra 1 , Mathew Maye 1
1 Chemistry, Syracuse University, Syracuse, New York, United States
Show AbstractEncoded biomolecular interactions play a key role in nanoparticle self-assembly, bioimaging and drug-delivery. Coupling such recognition with semiconductive quantum dot (q-dot) photoluminescence has led to several powerful sensing technologies and imaging probes. Still, several challenges, such as ease and stability of biofunctionalization, and tailorable biomaterial coverage remain. To address such issues, we have developed a new phase transfer protocol using the simple amino acids and small molecules that allow not only for rapid phase transfer, but also the preservation of quantum yields. Demonstrating the versatility of this method, the modified qdots readily undergo further ligand exchange in aqueous buffers, thus improving biofunctionalization. Preliminarily characterization of biofunctionalized qdots have been carried out using gel electrophoresis, NMR, dynamic light scattering, zeta-potential, and time resolved PL measurements.
9:00 PM - QQ3.7
Polyethyleneimine Functionalized ZnO Quantum Dots and Their Binding Interaction with Bovine Serum Albumin Protein.
Prachi Joshi 1 5 , Soumyananda Chakraborti 2 , Pinak Chakrbarti 2 , Surinder Singh 3 , Vinay Gupta 4 , Z. Ansari 5 , Virendra Shanker 1
1 LMD, NPL, New Delhi India, 5 , JMI, Delhi India, 2 , Bose Institute, kolkata India, 3 , UPRM, mayaguez United States, 4 , Delhi University, Delhi India
Show AbstractPolyethyleneimine (PEI) is an efficient gene transfer agent and has been successfully used as a nonviral vector for gene delivery both in vitro and in vivo [1,2]. It has been shown that PEI is more efficient in DNA transfection when formulated with serum albumin [3]. We have studied the interaction of bovine serum albumin (BSA) with (PEI) functionalized zinc oxide (ZnO) quantum dots (QDs). ZnO QDs have been synthesized by wet chemical route and further functionalized with PEI. X-ray diffraction measurement reveals the hexagonal wurtzite structure of as synthesized ZnO QDs and high-resolution transmission electron microscopy (HRTEM) micrograph suggests nearly spherical particles of size 3-6 nm. The ZnO/PEI QDs exhibit defect related yellow-green emission centered at 555 nm (2.23 eV) in water. The interaction between BSA and ZnO/PEI QDs has been studied using spectroscopic and calorimetric methods. Tryptophan quenching in BSA by ZnO/PEI nanoparticles indicates that a ground state complex formation is taking place between ZnO/PEI and BSA, where, the hydrogen bonding interaction is contributing towards the stability of the ground state complex. The fluorescence measurement suggests that the tertiary structure of protein is more stabilized by QDs in presence of denaturation agents such as guanidine hydrochloride (GdnHCl) and urea. The circular dichroism (CD) measurement reveals the conformational changes in secondary structure of protein that is reflected through the % change in α-helicity of BSA conjugated to ZnO/PEI. The formation of stable complex of ZnO/PEI with BSA indicate that this complex could enhance the PEI mediated gene delivery. Also, the synthesized ZnO/PEI QDs system may be used to understand the mechanism of PEI mediated gene delivery using fluorescence spectroscopy.
9:00 PM - QQ3.8
Synthesis and Physical Properties of Ophthalmic Polymer Containing Titanium Dioxide and Silver/Gold Nanoparticles.
A-Young Sung 1 , Ki-Hun Ye 1
1 , Daebul University, Jeonnam Korea (the Republic of)
Show AbstractRecently, nanoparticles of gold and silver has been applied to various fields due to antimicrobial property. Also, titanium dioxide is known to be very stable in chemical and physical aspects and has the highest refractive index among white pigments and also has a well defined particle size and dispersibility. Also, titanium dioxide decomposes organic compounds when activated with a photo-catalyst and there is a recent global trend of various applications of such characteristics in various fields. This study used titanium dioxide as a material to absorb UV rays with a high visible transmittance and refractive index. In this study we polymerized macromolecule material that silver/gold nano particles and titanium dioxide were added to HEMA(2-hydroxy ethyl methacrylate), NVP(N-vinylpyrrolidone) and MA(methacrylic acid) which is commonly used to produce ophthalmic contact lenses and measured the water content, refractive index, contact angle and transparencies for visible light. Also, the concentration of the used silver and gold nano colloid was 25 ppm respectively. The cast mould method was used in order to fabricate the ophthalmic lens and fabricated contact lens samples were hydrated for about 24hours. The results of the measurement showed that the refractive index, contact angle, water content and oxygen transmissibility of the contact lens polymer was 1.413~1.421, 35~42°, 38~42% and 9~13×10-9 cm/s ml O2/ml × mmHg respectively. The probe current graph was used in order to calculate oxygen transmissibility of the polymer. Optical transmittances of each wave length was 15%, 40% and 89% respectively for UV-A, UV-B and visible light. This polymer satisfied the basic properties required to produce ophthalmological lens.
Symposium Organizers
Larry A. Nagahara National Cancer Institute
Robert Sinclair Stanford University
Rashid Bashir University of Illinois, Urbana-Champaign
Thomas Thundat Oak Ridge National Laboratory
Wenbin Lin University of North Carolina, Chapel Hill
QQ4: Nanodevices for In-vitro Diagnostics
Session Chairs
Larry Nagahara
Thomas Thundat
Tuesday AM, November 30, 2010
Grand Ballroom (Sheraton)
9:00 AM - QQ4.1
Three-dimensional Flexible Nanoscale Field Effect Transistors as Localized Bioprobes.
Bozhi Tian 1 , Tzahi Cohen-Karni 2 , Charles Lieber 1 2
1 Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 2 School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States
Show AbstractNanoelectronic devices offer substantial potential for interrogating biological systems, although nearly all work has focused on planar or two-dimensional (2D) device designs. Such structures have necessitated applications in 2D sensing and extracellular recording, despite the inherently three-dimensional (3D) structure of biological systems. We show that this limitation can be overcome in a general manner through synthetic integration of a nanoscale field effect transistor (nanoFET) device at the tip of an acute-angle kinked silicon nanowire, where nanoscale connections are made by the arms of the kinked nanostructure and remote multilayer interconnects allow 3D probe presentation. The acute-angle probe geometry was designed and chemically realized by controlling 'cis' versus 'trans' crystal conformations between adjacent kinks, and the nanoFET was localized through modulation doping. 3D nanoFET probes exhibited conductance and sensitivity in aqueous solution independent of large mechanical deflections, and demonstrated high pH sensitivity. Additionally, 3D nanoprobes modified with phospholipid bilayers can enter single cells in a minimally-invasive manner to allow robust recording of intracellular potentials.
9:15 AM - QQ4.2
Sustainability of in Vitro Hippocampal Neuronal Cell Culture on Nanoscale Surfaces.
Asiful Islam 1 , Mohamed AbdElmoula 1 , Zheng Ma 1 , Michael Shannon 1 , Latika Menon 1
1 , Northeastern University, Boston, Massachusetts, United States
Show AbstractIn vitro neuron cell culture on nano-substrates is critical and challenging but an interesting advancement for neuro technology. We have cultured neuron cells on various nanoscale surfaces to compare neuronal viability and inter-actions of neurons with the nanoscale surface. Embryonic d 18 rat hippocampus neurons were mechanically dissociated and cultured on various nano-templates in laboratory condition with a constant temperature of 370 C in a 5% CO2 incubator. We demonstrated well-defined neuronal networks on Au-nanowire (GNW), gold-nanofilms(GNF), Titanium oxide (TiO2), Aluminum Oxide (Al2O3) and Gallium Nitrite (GaN) substrates using a positively charged polypeptides, Poly-D-Lysine (PDL) as an external coating. Cell survival was remarkable on nanowire substrates. The neuronal network interacted very closely with the nano-structures and in some cases the cells were rooted onto the nano-wire trenches. It has been established that the extracellular protein PDL was the crucial factor for neurites growth on the nanowire arrays which in general support the hypothesis that in an ‘in vivo system the adhesion molecules play an important role in proper neuronal development'. The pre- and post-synaptic affects of neuronal interactions on the surfaces of GNW templates were measured by Fura-2 and Fluo-2 Ca+ imaging. This study showed different signal patterns of neuronal stimulation in the post-synaptic stages. It is expected that electrical signal stimulation could be transferred to the neurons through micro and nanoscale-patterned substrates such as nanowires, although it might be important to study the individual cell-cell signaling pattern on the in vitro culture system to analyze the broader spectrum of neuronal defects and disorders in human.
9:30 AM - **QQ4.3
Low-Cost Technologies for Making Robust, Multiplexed, Sensitive and Quantitative Protein-based in Vitro Diagnostics.
James Heath 1 , Jun Wang 1 , Steven Millward 1 , Ophir Vermesh 1 , Udi Vermesh 1 , Young Shik Shin 1 , Habib Ahmad 1 , Arundhati Nag 1 , Samir An 1 , Heather Agnew 2 , Rosemary Rohde 2
1 Chemistry MC 127-72, Caltech, Pasadena, California, United States, 2 , Integrated Diagnostics, Culver City, California, United States
Show AbstractSequencing technology has advanced to the point where the benchmark of the $1000 genome is on the near horizon. However, the cost of quantitative measurements of protein biomarkers has remained relatively unchanged for the past 3 decades. Given that, marker-for-marker, protein diagnostics are the most informative of molecular diagnostics, finding approaches to drop the dramatically lower the cost of such measurements represents a significant scientific opportunity and a clinical need. In this talk, I will discuss several technologies we have developed with this goal in mind. These technologies include simple, stand alone (self-powered), and highly accurate microfluidics-based chips designed for automatically assaying a large panel of protein biomarkers from a pinprick of whole blood, as well as an antibody replacement technology called Protein Catalyzed Capture Agents, or PCC Agents. PCC agents are chemical constructs with exact molecular formulas, and are developed to exhibit the selectivity and sensitivity of high quality monoclonal antibodies, but with the added bonus of shelf-life stability. Finally, I will briefly discuss how some of these technologies, when integrated together, are allowing for new classes of clinical measurements on cancer patients.
10:00 AM - QQ4.4
Single Cell Dimension Patterned Conducting Polymer Surface for Control of Cells Adhesion and their Migration.
Esma Ismailova 1 , Alwin M.D. Wan 2 , George Malliaras 1 , Claudia Fischbach 3 , Delphine Gourdon 2
1 Bioelectronics, EMSE/CMP, Gardanne France, 2 MSE, Cornell University, Ithaca, New York, United States, 3 BME, Cornell University, Ithaca, New York, United States
Show AbstractConducting polymers offer unique opportunities as electrically “active” substrates for cell growth. Understanding of how cells interact with organic semiconductors and how that interaction can be controlled, would aid the potential design and implementation of numerous biomedical devices. We report pixelated surfaces in which individual pixels can be electrically switched between two states – one that promotes cell adhesion and one that does not. We investigated the effectiveness of such surfaces in the deterministic placement of various cells, as cancerous and non-cancerous cell lines, and in directing their migration. We discuss the dynamics of cell hopping among different pixels and correlated it with device geometry.
10:15 AM - QQ4.5
Micro and Nanostructured Polymer Thin Films for the Organization and Differentiation of Retinal Progenitor Cells.
Chi Wan Ko 1 2 , Jing Yao 3 4 , Michael Young 3 , Sarah Tao 2
1 Mechanical Engineering, MIT, Cambridge, Massachusetts, United States, 2 MEMS Design Group, Draper Laboratory, Cambridge, Massachusetts, United States, 3 , Schepens Eye Research Institute, Boston, Massachusetts, United States, 4 Department of Ophthalmology, Fudan University, Shanghai China
Show AbstractRetinal degenerative diseases, including retinitis pigmentosa and age-related macular degeneration, affect more than ten million people in the US. Currently, there is no proven visually beneficial treatment for these types of disease; however, stem cell-based therapy is a recent strategy which has the potential to preserve and restore vision in these conditions. In addition to replacing lost or diseased cells, transplanted cells may be able to rescue dying photoreceptors of the host retina. While studies have shown that retinal progenitor cells (RPCs) delivered by bolus injection can differentiate into retinal specific neurons after subretinal transplantation, they have not been able to maintain morphologic development, lamination, or extensive integration with the host retina. Therefore, a mechanism is needed to confer organization and instructional cues to these grafted cells. In this research, micro and nano-electro-mechanical systems (MEMS/NEMS) processing techniques were used to create biodegradable thin-film scaffolds to guide the differentiation and organization of stem cells for retinal tissue engineering. Through standard MEMS processes, including photolithography and reactive ion etching, a high throughput array of sub-micron features (500 nm to 1um) was fabricated into silicon wafers. A novel templating process was developed to then imprint these structures into biodegradable polycaprolactone (PCL) thin films (5 - 10um) with minimal deformation to the imprinted features. PCL was chosen due to its low melt temperature, adaptability to microfabrication processing, as well as its mechanical and bioresorptive properties. Furthermore, PCL thin films have been shown to be well tolerated long term when transplanted in the subretinal space of pigs. RPCs were cultured on PCL thin films, and cell responses to sub-micron topography of varying dimension and geometry were characterized using scanning electron microscopy and immunocytochemistry. Sub-micron features were found to definitively affect cell behavior. For example, while RPCs cultured on post structures demonstrated an early upregulation of differentiation markers, including rhodopsin and recoverin, RPCs cultured on a ridge-groove topography developed substantial elongation and parallel alignment in addition to upregulation. This unique structured PCL thin-film platform therefore provides a means to organize and differentiate RPCs in a controlled manner and offers potential as a clinical treatment for retinal degenerative diseases.
11:00 AM - QQ4.6
A Combinatorial Screening of Human Fibroblast Responses on Micro-structured Surfaces.
Kristian Kolind 1 , Morten Foss 1
1 , Interdisciplinary Nanoscience Center, Aarhus Denmark
Show AbstractBiomaterial surfaces structured with topographical features have been predicted to play an important role in the next generation of biomedical implants. Specific trends with regard to the influence of the topographical effect on cellular behavior are however challenging to establish due to differences in the topographical features and geometries in the various studies. Here, we demonstrate the use of a highly versatile combinatorial screening approach to identify the effect of 169 distinct surface topographies, consisting of pillars, on fibroblast proliferation and mechanical response. Altering the inter-pillar gap size of the structures revealed a significant change in fibroblast proliferation and identified obvious stress-induced changes in the cytoskeleton and focal adhesion morphology. Larger (4-6µm) inter-pillar gap sizes reduced fibroblast proliferation and elicited a strong elongation leading to a disruption of the actin cytoskeleton anchored primarily to focal adhesions located between the pillars. Smaller (1-2µm) inter-pillar gap sizes, on the contrary, caused the fibroblasts to proliferate comparable to cells on a non-structured surface with cells having a clear actin cytoskeleton attached to focal adhesions located mostly on top of the pillars. The approach reveals a strong correlation between the exact topographical periodicities and cellular responses such as cell proliferation, cell morphology and focal adhesion distribution.
11:15 AM - QQ4.7
Hybrid Nanogenerator for Concurrently Harvesting Biomechanical and Biochemical Energy.
Ying Liu 1 , Benjamin Hansen 1 , Rusen Yang 1 , Zhong Wang 1
1 Materials Science & Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
Show AbstractThe increasing demand for energy among human society makes energy harvesting from multiple sources available in our personal and daily environments is highly desirable. These sources include mechanical energy, such as walking, typing, speaking and breathing, even heart beating, and also chemical energy, such as biochemical energy in biofluid. Potentially they can be used not only for powering personal electronics, but also for future implantable sensor-transmitter devices for biomedical and healthcare applications. Here we present a hybrid energy scavenging device for prospective in-vivo applications. The hybrid device consists of a nanofiber nanogenerator for harvesting mechanical energy, and a biofuel cell for harvesting the biochemical (glucose/O2) energy, which are the two types of energy available in-vivo. The nanogenerator uses multiple aligned nanofibers of the piezoelectric polymer poly(vinylidene fluoride) for power generation, and gives average output of tens of millivolts and about one nanoampere. The biofuel cell uses enzymes (Glucose Oxide and Lacasse) deposited on carbon nanotubes as electrochemical electrode and gives output of the same order. The two energy harvesting approaches can work simultaneously or individually, thereby boosting output and lifetime. For further demonstration of its performance, weconstructred a ‘self-powered’ nanosystem by powering a ZnO nanowire UV light sensor using our hybrid nanogenerator. As reported from other research, the highest reported output voltage of various mechanical nanogenerators is more than one volt, while the highest theoretical output of enzymatic biofuel cell is around one volt. By optimizing various factors and integrating multiple devices together, the output of our hybrid nanogenerator can be further enhanced in the future. Reference:[1] Hansen, B. J.+; Liu, Y.+; Yang, R. S. ; Wang, Z. L. Hybrid Nanogenerator for Concurrently Harvesting Biomechanical and Biochemical Energy. ACS Nano, Online.[2] Xu, S.; Qin, Y.; Xu, C.; Wei, Y.; Yang, R.; Wang, Z. L. Self-powered Nanowire Devices. Nature Nanotech. 2010, 5, 366-373.[3] Chang, C.; Tran, V. H.; Wang, J.; Fuh, Y.; Lin, L. Direct-Write Piezoelectric Polymeric Nanogenerator with High Energy Conversion Efficiency. Nano Lett. 2010, 10, 726-731.[4] Heller, A. Miniature Biofuel Cells. PCCP 2004, 6, 209-216.
11:30 AM - **QQ4.8
An Ultra-sensitive Polymer Composite Lab-on-chip Platform for Disposable Cardiac Diagnostic Applications.
Ramgopal Rao 1
1 Electrical Engineering, IIT Bombay, Mumbai India
Show AbstractEfficiency of medical diagnostics relies on fast, sensitive, inexpensive and disposable biosensors to detect the respective target analytes. During the past few decades, there have been spectacular advancements in micro-electro-mechanical systems which facilitated the development of a “nano-mechanical motion” based sensors namely micro-cantilevers for biological and biochemical sensing applications. Here we present the development of a novel polymer composite micro-cantilever sensor based lab-on-a-chip for cardiac diagnostics. In comparison to the conventional silicon based micro-cantilevers, these polymer devices offer better sensitivity with reduced process complexity and cost. The embodiment of the sensor is an SU-8 microcantilever chip with integrated SU-8/nanoparticle composite piezoresistor for on-chip electrical transduction. The fabrication and device characterization of these polymer composite micro-cantilevers are presented in this paper. The devices showed a deflection sensitivity of ~1 ppm for 1 nm of deflection. The application of these sensors in the early detection of of Acute Myocardial Infraction (AMI) is also detailed in this paper. Myoglobin being a specific and one of the early markers of AMI, is being considered here as the target molecule to be detected. For this, the polymer micro-cantilever surfaces are selectively immobilized with anti-myoglobin by following a specific silanization protocol. Then the functionalized devices are incubated inside a low volume PDMS liquid cell fabricated using a soft lithography technique. These polymer composite micro-cantilevers are connected to a wheastone’s bridge based signal conditioning circuit for dynamic recording of the output. Biomolecular interaction between the target molecule myoglobin and the anti-myoglobin on the micro-cantilever surface leads to a surface stress change that gives a change in resistance of polymer composite piezo-resistor and hence a change in the bridge voltage output. The experiments were carried out with different concentration of myoglobin to find out the lower limit of detection using these sensors.
12:00 PM - QQ4.9
Lateral Fusion of Lipid Membranes to Nanoscale Functionalized Probes.
Ben Almquist 1 , Nick Melosh 1
1 Materials Science, Stanford University, Stanford, California, United States
Show AbstractThe ability to specifically and nondestructively incorporate inorganic structures into or through biological membranes is a key step toward realizing full bioinorganic integration, such as arrayed on-chip patch-clamps, drug delivery, and biosensors. However, molecular delivery and interfaces to inorganic objects, such as patch-clamp pipettes, generally rely upon destructive formation of membrane holes and serendipitous adhesion, rather than selective penetration and attachment into the bilayer itself. Because a key aspiration of biomaterials is seamlessly interfacing artificial materials with natural components, a more benign means to penetrate through the cell membrane is required. While surface modification techniques have been highly successful at controlling cell mobility, proliferation, and differentiation on two-dimensional surfaces, bridging across the cell membrane itself has been much less studied. A prime example of such a system is membrane proteins, whose outer surface is designed to specifically interact with the interior of the cell membrane lipid bilayer. The tight junction between the lipid and protein eliminates constitutive ion or protein leakage, allowing membrane proteins to regulate the chemical flux through the bilayer.In this talk, I will discuss the development of nanofabricated probes that spontaneously insert into the hydrophobic membrane core by mimicking the hydrophobic banding of transmembrane proteins, forming a well-defined bio-inorganic lateral junction and enabling through-membrane access. These biomimetic ‘stealth’ probes consist of hydrophilic posts with 2-10 nm hydrophobic bands formed by molecular self-assembly, and are easily fabricated onto a variety of substrates including silicon wafers, nanoparticles, and atomic force microscope (AFM) tips.By fabricating this architecture onto AFM probes, we have directly measured the penetration behavior and interface strength of different molecular functionalities within the bilayer. It has been found that following insertion, the stealth probes remain anchored in the center of the bilayer, while purely hydrophilic probes have no preferred location. The strength of the stealth probe adhesion varies greatly with molecular structure, indicating that in addition to hydrophobicity, the physical nature of the functional band plays a crucial role in regulating interface stability. Moreover, the consequences of geometric factors such as band thickness have been established. By selectively choosing the desired properties of the hydrophobic band, it is possible to tune the failure strength of the interface from values comparable to that of pristine lipid vesicles to a fraction of the strength. This capability is crucial for adapting the functional band architecture to a variety of platforms, and our efforts relating to the development of nanoparticles for drug delivery and arrayed on-chip patch clamps will be discussed.Ref: BD Almquist & NA Melosh, PNAS, 107, 5815 (2010).
12:15 PM - QQ4.10
Self-Reporting Porous Silicon Nanomatrix for Biosensing.
Michelle Chen 1 , Frederique Cunin 2 , Vinh Diep 3 , Michael Sailor 4 1 2
1 Bioengineering, University of California, San Diego, La Jolla, California, United States, 2 Material Science, University of California, San Diego, La Jolla, California, United States, 3 Nanoengineering, University of California, San Diego, La Jolla, California, United States, 4 Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, United States
Show AbstractA label-free porous silicon (pSi) biosensor consisting of a multilayered optical nanostructure was designed to perform simultaneous separation and monitoring of biomolecular interactions. pSi is a high surface area material whose pore dimensions can be tuned across biologically relevant length scales. The large surface to volume ratio enables sensitive detection requiring a small sample volume (fM to nM). Additionally, the optical sensing properties of pSi allow in situ, label-free and real time quantification of molecular parameters such as transport rates, surface charge, and physical dimensions. The stratified porous nanostructures were prepared by electrochemical etching. Pore size-dependent molecular transport was monitored by tracking the change in refractive index of the various stratified layers using optical interferometry. Since the diffusion profile of a protein in a restricted diffusion environment is controlled by pore diameter as well as by its physical size, the time-resolved optical interferometry data provide an estimate of the physical dimensions of the molecule. Sizes of the tested proteins (Albumin, Protein A, IgG, and insulin) were verified by dynamic light scattering. Diffusion profiles were fit to Fick’s 2nd law to quantify the transport phenomenon.Molecular diffusion in a precisely controlled pSi structure exhibits a pore diameter and molecular size dependent transport phenomenon. Results of the analysis indicate that molecular diffusion in the precisely controlled pSi nanostructure is also dependent on surface chemistry, which can be used to modify the rate of transport. Compared to conventional optical sensors, the “self-reporting” pSi matrix provides a new platform for direct measurement and separation of analytes within the material.
QQ5: Nanotherapeutics
Session Chairs
Tuesday PM, November 30, 2010
Grand Ballroom (Sheraton)
2:30 PM - **QQ5.1
NanoBees: A Strategy for Safe and Effective Delivery of Cytolytic Peptides to Tumors.
Samuel Wickline 1
1 , Washington University, St Louis, Missouri, United States
Show AbstractThe in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, non specificity, in vivo degradation, and lack of a delivery vehicle. We have developed a specific strategy to synthesize a nanoscale delivery vehicle for cytolytic peptides by incorporating the amphipathic peptide melittin, a 26 a.a. cationic amphipathic constituent of bee venom, into the outer lipid monolayer of a perfluorocarbon nanoparticle. The favorable pharmacokinetics of this nanocarrier allows higher accumulation of melittin in murine tumors and a dramatic reduction in tumor growth without any apparent signs of toxicity. Alternatively, direct assays demonstrate that molecularly targeted nano carriers selectively deliver melittin to multiple tumor targets (i.e. endothelial cells and cancer cells) through a novel lipid hemifusion mechanism without disrupting the cell membrane barrier to trigger apoptosis and cause regression of precancerous dysplastic lesions. The ability to restrain the wide-spectrum lytic potential of a potent cytolytic peptide in a nano vehicle combined with the flexibility of passive or active molecular targeting to treat cancer at multiple stages represents an innovative molecular design for chemotherapy with broad spectrum cytolytic peptides.
3:00 PM - **QQ5.2
Delivery of Nanotherapeutics Using a Cellular Trojan Horse.
Susan Clare 1 , MiRan Choi 1 , Sunil Badve 2 , Harikrishna Nakshatri 1 , Shalmali Dharmadhikari 3 , Navin Bansal 3 , Rizia Bardhan 4 , Naomi Halas 4
1 Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States, 2 Pathology, Indiana Univeristy School of Medicine, Indianapolis, Indiana, United States, 3 Radiology, Indiana Univeristy School of Medicine, Indianapolis, Indiana, United States, 4 Electrical and Computer Engineering, Rice University, Houston, Texas, United States
Show AbstractBackground: Cancer nanotherapeutics must be reliably, efficiently and uniformly delivered to be successful. Significant barriers to delivery are present in all solid tumors; including chaotic and non-uniform blood flow, non-uniform tumor vessels leakiness and high interstitial fluid pressures. Metastatic lesions in the brain have a delivery challenge unique to their location: The blood-brain barrier. Monocytes/macrophages are recruited to tumors by a chemoattractant gradient. Our strategy takes advantage of this recruitment, and of the monocytes/macrophages innate phagocytosis ability in order to load them with nanotherapeutics, and thereby to create a Trojan horse. The nanotherapeutics studied to date include gold-silica nanoshells, which convert absorbed infra-red radiation into thermal energy, and nanoencapsulated drug.Materials and Methods: An orthotopic human xenograft was established in nude mice as a model of primary breast cancer. Monocytes were isolated from human whole blood and loaded with gold-silica nanoshells. The loaded macrophages were injected via the tail vein into the systemic circulation of the mice. Uptake of the nanoshell-laden macrophages by the xenografts was monitored using magnetic resonance imaging. Once uptake was verified, the tumors were irradiated with a near-infrared laser (0.5 W, 5mm spot size) for varying lengths of time. A brain seeking breast cancer cell line (MDA-MB-231 BR) was used to produce intracranial metastases. Monocytes were loaded ex vivo with fluorescent microparticles and injected into the systemic circulation via the tail vein. Brains were removed at necropsy and the presence of the fluorescent microparticles within the metastases determined using two-photon microscopy.Results: The in vivo delivery of the macrophages loaded with nanoshells to the orthotopic human xenograft tumors was verified. Significant uptake was observed at 24 hours after injection. Uptake was also observed in the lungs, liver and spleen. An increase of ~ 30°C at the tumor skin was noted following 90 seconds of irradiation of the orthotopic tumor. Homing-in of the nanoparticle-laden macrophages to the metastatic lesions in the brain was also observed.Conclusions: Macrophages offer a novel means by which to deliver nanotherapeutics to both primary malignant and metastatic lesions.
3:30 PM - **QQ5.3
Engineering Cooperative Nanosystems for Cancer Diagnosis and Therapy.
Sangeeta Bhatia 1 2 3
1 , Howard Hughes Medical Institute, Cambridge, Massachusetts, United States, 2 , MIT, Cambridge, Massachusetts, United States, 3 , Brigham and Women’s Hospital, Boston, Massachusetts, United States
Show AbstractOur laboratory is interested in engineering tools and systems using multifunctional nanoparticles to transform the diagnosis and treatment of cancer. We aim to integrate nanomaterials having enhanced nanoscale properties and bioresponsive functionalities with our knowledge of the tumor microenvironment to explore this paradigm. Towards this aim, we have developed and investigated nanoparticle conjugates based on three nanoparticle cores that harness features of the nanoscale: semiconductor quantum dots that exhibit size-based optical properties, dextran-coated iron oxide particles whose assembly alters the spin-spin relaxation time of hydrogen protons on magnetic resonance imaging, and polymer-coated gold nanorods that interact resonantly with near-infrared light. Our studies have shown how these nanoparticles specifically designed to enhance their interaction with the biological environment can help achieve targeting, triggered self-assembly, remote actuation with radiofrequency fields, sensing of kinase activity, and delivery of short interfering RNAs. In collaboration with Erkki Ruoslahti (Burnham Institute), we have explored how decorating the surface with peptides obtained from an in vivo phage display can alter the properties of these nanoparticles and control their trafficking. To increase the accumulation of the nanoparticles at the tumor site we are exploring in vivo self-assembly of these particles. Our approach is inspired by platelets-natural microparticles that normally circulate in a latent form but can home to sites of injury and transform to an activated state, whereby they adhere and recruit more platelets. This results in assemblies of magnetic nanoparticles that may then acquire emergent properties, allowing either their enhanced visualization or remote actuation of drug delivery. More recently, we have also emulated biological systems where biological components remotely communicate via biological intermediates, such as tissue-resident macrophages that participate in the recruitment of circulating neutrophils. The resultant nanoparticle formulations then act as a "system" to produce emergent behaviors for enhancing diagnosis and therapy. Ultimately, we anticipate that the next-generation therapeutics will be modular components of cooperative systems that provide diagnostic and therapeutic benefits that can be customized for different types of tumors and stages of tumor progression.
4:45 PM - QQ5.5
Hybrid Nanoparticles for Platinum Anticancer Drug Delivery.
Joseph Della Rocca 1 , Rachel Huxford 1 , Erica Duggan 1 , Wenbin Lin 1
1 Chemistry, University of North Carolina, Chapel Hill, North Carolina, United States
Show AbstractDespite the tremendous advances in our knowledge of the fundamental biology and progression of many diseases, we have not yet witnessed comparable advances in the treatment of these diseases. One of the major problems with small molecule therapeutics is their nonspecific distribution, which leads to low accumulation in their intended parenchymal sites. A potential solution to increase the specificity and potency of biomedical agents is to incorporate them within a nanoparticle. Nanomaterials offer many advantages to small molecule drugs including high agent loading, long circulation half-lives, the ability to incorporate multiple agents and to be targeted to specific regions within the body. Hybrid nanomaterials are an emerging platform for the delivery of biomedically relevant agents. These nanomaterials are a blend of organic and inorganic components and retain the beneficial properties of both. We have developed several hybrid nanomaterials for the delivery of platinum based anticancer agents, namely cisplatin and oxaliplatin derivatives. These nanoparticles contain very high agent loadings and are designed to be inert under normal physiological conditions. However, in the highly reducing environment inside cancer cells, the platinum drugs are rapidly released to lead to cancer cell apoptosis. Preliminary in vitro assays demonstrate that these nanoparticles have comparable or superior activity to cisplatin or oxaliplatin over several cancer lines. Additionally, the surface conjugation of an appropriate targeting ligand increases the overall potency of the construct against these cell lines. These hybrid nanoparticle systems show tremendous potential as the next generation anticancer nanotherapeutics.
5:00 PM - QQ5.6
Magnetic Nanoemulsions for Triggered Hyperthermic Chemotherapy.
Dattatri Nagesha 1 , Srinivas Ganta 2 , Mathew Chamberlain 1 , Lauren Moore 1 , Mansoor Amiji 2 , Srinivas Sridhar 1
1 Physics, Northeastern University, Boston, Massachusetts, United States, 2 Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States
Show AbstractNanotechnology-enabled drug delivery systems have the promise to improve drug delivery at tumor site particularly in the treatment of multidrug resistant (MDR) tumors. Among the various nanotechnology platforms, nanoemulsions (NE) are unique and most versatile especially for the delivery of insoluble or hydrophobic drugs. Cancer cell response to these NE can be further enhanced through the use of triggered release or stimuli to control and regulate drug release after these NE have reached the disease site. Using change in temperature as the trigger, NE containing temperature sensitive phospholipids can be formulated to modulate drug release from within these NE. Towards this end, we have developed magnetic nanoemulsions (Mag-NE) - a multifunctional thermosensitive nanoemulsion loaded with Doxorubicin stearate (Dox), a pro-apoptotic chemotherapeutic agent, and magnetic iron oxide (Fe3O4) nanoparticles (MagNPs). Mag-NE were formulated from DPPC, MPEG-2000-DSPE, Egg phosphotidylcholine and pine-nut oil. The 100 nm average size of Mag-NE is ideal to take advantage of passive targeting and accumulation in the tumor through the enhanced permeability and retention (EPR) effect. Presence of MagNPs facilitate conversion of applied oscillating magnetic field energy into heat, leading to instability of the Mag-NE at approximately 40-45C, resulting in drug release within the tumor mass. The use of external oscillating magnetic field, which can penetrate deep within tissue without damaging healthy cells, along with MagNPs to trigger release of Dox from within NE offers the capability to ensure local release at the site of accumulation. This localized hyperthermia will act as an adjuvant to chemotherapy to overcome MDR through higher drug accumulation and decrease in functional P-glycoprotein efflux pump resulting in increased cell kill. Results from the in vitro magnetically triggered release of Dox from Mag-NE in SKOV3 and SKOV3TR human ovarian adenocarcinoma cells lines will be presented. This work was supported by IGERT Nanomedicine Science and Technology Program (NSF 0504331) and Northeastern University.
5:15 PM - QQ5.7
Sonosensitive Nanoparticle Formulations for Cavitation-mediated Ultrasonic Enhancement of Local Drug Delivery.
Sarah Wagstaffe 1 , Manish Arora 1 , Constantin Coussios 1 , Heiko Schiffter 1
1 Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford United Kingdom
Show AbstractInertial cavitation, namely the rapid expansion and subsequent violent collapse of micron-sized cavities under the effect of ultrasound-induced pressure variations, has widely been considered as an undesirable phenomenon for in vivo biomedical applications. This is mainly because of its highly stochastic nature and difficulties in its reliable initiation in vivo using moderate ultrasound pressure levels. Lowering of the pressure required to initiate cavitation, known as the cavitation threshold, has been previously addressed with the use of ultrasound contrast agents (encapsulated stabilized micron sized bubbles). However, such agents do not readily extravasate into tumours and other target tissues due to their large size. The present work investigates the engineering of novel nanoparticles capable of facilitating initiation of inertial cavitation in the context of ultrasound-enhanced local drug delivery. We aim to manufacture nanoparticulate formulations which are size-engineered to target tumour vasculature whilst presenting high surface roughness and hydrophobicity, thus facilitating the initiation of inertial cavitation with moderate ultrasound amplitudes and the low energy levels typically deployed by diagnostic systems. Thus far, a range of nanoparticle manufacture techniques have been explored to achieve these characteristics, including a modified solvent evaporation technique that incorporates additional volatile reagents to create the cavitation-inducing pores after freeze-drying. Core-shell nanoparticle production methods have been pursed to incorporate a gas body in the core of these particles and additionally a modified spray-drying process has been investigated as an alternative and easily scalable manufacture route of nanoparticulate formulations. Following production, particle formulations are analysed using electron microscopy methods, dynamic sizing techniques and surface chemical analysis methods. The degree to which they are able to lower the inertial cavitation threshold is also quantified by exposing particle suspensions in various media such as water or blood to increasing levels of ultrasound excitation, enabling evaluation of their potential usefulness for ultrasound-mediated drug delivery.
5:30 PM - QQ5.8
Nanopillared Metal Stent for Superior Endothelialization and Controlled Drug Release.
Karla Brammer 1 , Mariana Loya 1 , Sungho Jin 1
1 , Univ. of California, San Diego, La Jolla, California, United States
Show AbstractDrug-eluting stents benefit millions of patients with cardiovascular complications. However, due to the late-stent-thrombosis concerns and limited endothelialization associated with drug-eluting stents, bare metal stents are receiving much attention in recent years. As we have previously demonstrated, endothelial cells are positively influenced by the presence of nanoscale surface texturing[1]. We have created radially emanating metallic nanopillar structures on the surface of MP35N (Co-Ni-Cr-Mo) stent alloy wires using an argon RF plasma processing technique[2,3]. We have demonstrated that our high aspect ratio, vertically aligned pillar type of nanostructure is very useful for favorably stimulating the endothelial cell response in vascular stent applications, where it is critical that the material surface elicit properties that enable full integration of the stent as a part of the vessel wall and facilitate structurally sound endothelialization. It is shown that the superior endothelial cell growth is also combined with a well organized monolayer formation and improved endothelialization on the MP35N stent alloy nanopillar structure. In addition, the nanopillar structure with deep grooves in between offers a much increased surface area and adds an important capability for trapping drugs and controlled slow release for therapeutics that minimize restenosis (narrowing of the blood vessel). With the demonstrated significant results, we believe that these optimistic findings are likely to (i) contribute to new surface design concepts for bare metal stents utilizing nanotechnology, (ii) eventually lead to medical advances toward mitigating stent thrombosis (clotting) and restenosis, and (iii) eliminate the need for polymer modified stent surfaces which could cause unwanted long term health problems.[1] KS Brammer, et al, “Enhanced Cellular Mobility guided by TiO2 Nanotube Surfaces”, Nano Lett. 8(3), 786 (2008).[2] MC Loya, KS Brammer,et al, “Radially Arrayed Nanopillar Formation on Metallic Stent Wire Surface via RF Plasma”, Acta Biomate 6, 1671 (2010).[3] MC Loya, KS Brammer, et al, "Plasma-induced nanopillars on bare-metal coronary stentsurface for enhanced endothelialization." Acta Biomater. (2010, in press).
5:45 PM - QQ5.9
Carbon Nanotube Membranes for Programmed Transdermal Drug Delivery.
Ji Wu 1 , Kalpana Paudel 2 , Audra Stinchcomb 2 , Bruce Hinds 1
1 Chemical and Materials Engineering, Univ. of Kentucky, Lexington, Kentucky, United States, 2 College of Pharmacy, Univ. of KY, Lexington, Kentucky, United States
Show AbstractAddiction treatment is one of the most difficult health care challenges due to the mixture of complex changing neurochemical pathways and psychological behavior. A promising system would be a dosing regimen (within a doctors’ prescription limit) can be remotely programmed to account for daily environmental factors, patient input, and counselor feedback from phone interviews or internet-based surveys. Needed for this system is an ultra low power, compact, and programmable delivery device not currently available with electroporation or mechanical pumps.Membranes made of carbon nanotubes possess many advantageous attributes that include: 1) atomically flat graphite surface allows for ideal fluid slip boundary conditions 100,00 times faster than conventional pores [1] 2) the cutting process to open CNTs inherently places functional chemistry at CNT core entrance to act as chemical gatekeepers and 3) CNT are electrically conductive allowing for electrochemical reactions and application of electric fields gradients at CNT tips. Thus CNT membranes are and ideal candidate to have a voltage controlled membrane as the active element in a transdermal drug delivery device.[2] CNT membranes were functionalized with highly-charged anionic dye molecules to induce a highly efficient electroosmotic flow. The anionic charge density on CNTs was first enhanced through diazonium electrochemical modification followed by a quad-anionic dye amine functionalization. It was found that fluxes of both cationic and neutral molecules through the CNT membrane have been greatly increased under negative biases. High electro-osmotic flows of 0.05 cm/s at -300mV bias have been observed with 50% ion efficiency. This allows a 40 fold increase in pumping power efficiency compared to conventional membrane materials thereby allowing a watch battery to continuously pump for 12 days. These membranes were integrated with a nicotine formulation to obtain switchable transdermal nicotine delivery rates on human skin (in vitro) and are consistent with a Fickian diffusion in series model. The transdermal nicotine delivery device was able to successfully switch between high (1.3±0.65 µmol/hr-cm2) and low (0.33±0.22 µmol/hr-cm2) fluxes that coincide with therapeutic demand levels for nicotine cessation treatment [3]. Clonidine delivery through CNTs and human skin also matches the traditional five-day opioid withdrawal symptom treatment that requires variable delivery rates ranging from 1.7 to 5.4 nano-mole/hr.cm2. [1] Majumder, M., Chopra, N., Andrews, R. & Hinds, B.J. Nanoscale hydrodynamics - Enhanced flow in carbon nanotubes. Nature 438, 44-44 (2005).[2] Majumder, M., Zhan, X., Andrews, R. & Hinds, B.J. Voltage gated carbon nanotube membranes. Langmuir 23, 8624-8631 (2007).[3] J. Wu, K. S. Paudel, C. Strasinger, D. Hammell, A. Stinchcomb, B.J. Hinds Programmable Transdermal Drug Delivery of Nicotine using Carbon Nanotube Membranes. Proc. Nat. Acad. Sci. in-press (2010)
QQ6: Poster Session: Nanofabrication, Nanodevices, and Nanosensing Techniques for Biomedical Applications
Session Chairs
Rashid Bashir
Wenbin Lin
Larry Nagahara
Robert Sinclair
Thomas Thundat
Wednesday AM, December 01, 2010
Exhibition Hall D (Hynes)
9:00 PM - QQ6.1
Physical Electrochemistry of Nanowell Array Electrodes toward Nanomedicine.
SeongWung Kang 1 2 , InRok Whang 1 2 , Tomoji Kawai 1 , BaeHo Park 1 2 , Tanaka Hidekazu 1 , HeaYeon Lee 1 2
1 , Osaka university, Osaka Japan, 2 , Konkuk University, Seoul Korea (the Republic of)
Show AbstractUltrasmall electrodes offer advantages when employed in physical electrochemical research and applications. The advantages can be expected to be achieved to a greater extent with nanoscaled array electrodes. Furthermore biocompatible integrated nanoarray pattern requires the fabrication of appropriately designed nanomatrix for high sensitivity homogenous assays, which are capable of ultimately mimic the physiological environment. We reported the nanomatrix geometry of a well-oriented nanowell array derived from nanofabrication technology which can easily be employed for digital detection with a high S/N ratio, miniaturization, integrated assays and single molecule analysis. In this present, we describe the diffusion principles of nanowell array electrochemistry toward nanomedicine. Nanowell array electrodes were enhanced diffusion rates and thus can be used to measure the kinetics of faster electrode reactions. The enhanced or diminished redox currents are measured at the nanoscaled electrode depending on the redox species, i.e. anionic or cationic. An important consideration in the nanowell array electrochemistry is the background current or charging current. This is proportional to the total geometric area of the nanoelectrode numbers. However the diffusion-controlled current in the electrical double layer will be proportional to the total active electrode area of the nanoelectrode array. This means that an effective enhancement of the S/N is obtained. This represents an important advantage to the analytical use of nanoelectrode arrays. It is envisioned that the miniaturized integrated nanowell array-chip system has excellent advantages over conventional instrumental systems for analysis of biomaterials such as compactness, economical, rapid, and multiplex capability. Furthermore, the nanowell array-sensorchip system should be compatible with a variety of nanobiodevices that aim at high throughput analysis.
9:00 PM - QQ6.10
Multifunctional Colloidal Nanobeads Containing Inorganic Nanoparticles or Their Assemblies.
Nadja Bigall 1 , Riccardo Di Corato 1 , Liberato Manna 1 , Teresa Pellegrino 1
1 Nanobiotech, Italian Institute of Technology, Genova Italy
Show AbstractColloidal solutions of inorganic nanoparticles, even though being exceptional new materials of high interest, are yet limited in their application spectrum, since e.g. the nanoparticles cannot simply be separated from their surrounding medium, or additional functionalities are missing. Hence, the assembly of nanoparticles is an important branch of nanoscience. Especially, embedding inorganic nanoparticles into a polymer shell yielding nanobeads in the diameter range tunable from 30 nm to 400 nm [1] is of tremendous interest, since several of the attractive and novel properties of the nanocrystals can be joined, conserved, and even increased inside these polymer beads. For example, nanobeads containing superparamagnetic nanoparticles are under current investigation as contrast agents in magnetic resonance imaging, hyperthermia, cell separation and magnetically guided drug delivery. Colloidal supercrystals from assembled nanoparticles, as well as a system containing these supercrystals embedded into a polymer shell, also display highly interesting new materials with applications especially in biomedical imaging. Here, the magnetic interaction between the nanoparticles is increased due to the minimized particle-to-particle distance, which results in an enhanced acceleration of the colloidal supercrystals within externally applied magnetic fields.
The topics discussed will include the synthesis and possible applications of polymer nanobeads containing superparamagnetic nanocrystals, luminescent quantum dots, and metal nanoparticles, as well as nanobeads with two or more different nanocrystal species. Additionally, a variety of different types of nanocrystal shapes is tested with respect to either their tendency to assemble into highly ordered supercrystals (in the absence of polymer) or to their spatial distribution within polymer beads. For introducing additional functionality into these nanoscale systems, different molecules can be coupled as side chains to the polymer, either before or after the nanobead synthesis, yielding for example pH sensitive nanobeads with possible applications in drug release. The as-prepared colloidal dispersions are characterized by transmission electron microscopy, photoluminescence spectroscopy, dynamic light scattering and confocal microscopy etc., and hyperthermia measurements will be presented.
[1] Di Corato R., Piacenza P., Musaro M., Buonsanti R., Cozzoli P.T., Zambianchi M., Barbarella G., Cingolani R., Manna L., Pellegrino T. Macromol. Biosci. 2009 , 9, 952–958.
9:00 PM - QQ6.11
Wetting Pattern on TiO2 Nanostructure Films and its Application as a Template for Selective Materials Growth.
Yuekun Lai 1 2 , Yuxin Tang 1 , Dangguo Gong 1 , Changjian Lin 2 , Zhong Chen 1
1 School of Materials Science and Engineering, Nanyang Technological University, Singapore Singapore, 2 College of Chemistry and Chemical Engineering, Xiamen University, Xiamen China
Show AbstractWettability of solid surface is an important property and is governed by the chemical composition and geometrical structure [1,2]. Two extremely cases, superhydrophobicity with a water contact angle (CA) above 150° and superhydrophilicity with CA below 5°, have attracted much interest due to their importance in theoretical research and practical application [3-5]. Micropatterns with different physical or chemical properties have been frequently acted as the microtemplates for fabricating various functional materials and devices. In this work, we have developed a novel method for constructing superhydrophilic-superhydrophobic micropattern by using photocatalytic lithography of the self-assembled monolayers (SAMs) on the TiO2 nanotube structure substrates. The micropattern is based on the SAM technique on the special nanostructure TiO2 film to achieve superhydrophobicity and the sectional photocatalytic decomposition of PTES molecules on the surface of TiO2 nanotube films to realize superhydrophilicity in ambient conditions. The UV irradiated regions become superhydrophilic owing to the formation of hydrophilic silica, while the masked areas remain superhydrophobic. Moving further, we will show that the superhydrophilic-superhydrophobic micropatterns could be used as a template to selectively grow functional materials. One example given is the coating of octacalcium phosphate (OCP) pattern by electrophoretic deposition. Using the technique, the shape and thickness of the micropattern are easily controllable. It is demonstrated that the superhydrophilic-superhydrophobic micropatterns is a very promising technique for constructing well-defined nano-structured functional materials and micro-nano devices.Reference:[1] R. Wang, K. Hashimoto, A. Fujishima, M. Chikuni, E. Kojima, A. Kitamura, M. Shimohigoshi, T. Watanabe, Nature 388 (1997) 431. [2] K. Ichimura, S.K. Oh, M. Nakagawa, Science 288 (2000) 1624.[3] Y.K. Lai, Z.Q. Lin, J.Y. Huang, Z. Chen, L. Sun, C.J. Lin, New J. Chem. 34 (2010) 44.[4] Y.K. Lai, C.J. Lin, J.Y. Huang, H.F. Zhuang, L. Sun, T. Nguyen, Langmuir 24 (2008) 3867.[5] Y.K. Lai, X.F. Gao, H.F. Zhuang, J.Y. Huang, C.J. Lin, L. Jiang, Adv. Mater. 21 (2009) 3799.
9:00 PM - QQ6.12
Nanofabrication and Detection of Molecular Shuttles Powered by Kinesin Motor Protein.
Daniel Oliveira 1 , Kim Domyoung 2 , Mitsuo Umetsu 2 1 , Tadafumi Adschiri 1 , Winfried Teizer 3 1
1 World Premier International - Advanced Institute for Materials Research, Tohoku University, Sendai Japan, 2 Department of Biomolecular Engineering, Tohoku University, Sendai Japan, 3 Department of Physics and Astronomy, Texas A&M University, College Station, Texas, United States
Show AbstractMolecular shuttles, also referred to as nanotransporters, are among the best known naturally occurring biological nanomachines, performing a variety of tasks such as vesicles transport and mitosis. In this system, a given protein (e.g., kinesin) steps along a cytoplasmic system of fibers (microtubules) employing energy harnessed by the hydrolysis of adenosine-5'-triphosphate (ATP). Recent efforts to engineer tailor-made artificial nanotransport systems in order to carry out directional transport of nanoobjects in a cell-free environment are thus hardly surprising. In a typical design, ATP-fueled kinesin motor proteins are immobilized on a glass surface while microtubules loaded with cargo are propelled over the motors. Alternatively, molecular shuttles can be assembled mimicking the natural cell`s intracellular transport mechanism where the kinesin protein moves over microtubules tracks. From a device engineering perspective, the latter approach for molecular shuttles nanofabrication is more appealing since multiple microtubules tracks with varying directions can be designed in the same device; moreover, bidirectional cargo transport can be achieved on the same track if different motor proteins are used (e.g., kinesin and dynein). Therefore, it is conceivable to direct such concept to the development of nanoelectromechanical systems capable of nanoscale transport of highly functional hybrid nanomaterials. The motion of hybrid nanomaterials attached to kinesin via biotin-streptavidin linkages has been visualized by fluorescence microscopy, with the goal of analyzing run lengths and velocities of the molecular shuttles. Such experiments shed light on the transport of functional hybrid nanoparticles by kinesin-based molecular shuttles to be potentially employed as drug delivery systems. This work was supported by the WPI Program.
9:00 PM - QQ6.13
Fabrication of Nanofluidic Channels using Core-shell Nanofibers as Sacrificial Molds.
Shiyou Xu 1 , Yi Zhao 1
1 Biomedical Engineering, Ohio State University, Columbus, Ohio, United States
Show AbstractNanofluidic channels have received considerable attentions since such structures enable high throughput analysis and multiparameter detection of minute amount of molecules by allowing nano liquid chromatography and nano capillary electrophoresis. In this paper, we present a novel fabrication approach to create nanochannels with controllable diameters using core-shell nanofibers as sacrificial molds.In this process, SU-8 microstructures are first patterned on a single crystal silicon substrate using standard photolithography. Poly(vinyl pyrrolidone)(PVP) nanofibers are electrospun on top of SU-8 microstructures. The nanofibers are aligned perpendicular to the longitudinal direction of the SU-8 microstructures by creating an electric field by external conductive collecting pads. The flow rate of the electrospinning process is adjusted so that there is no obvious sagging down of the nanofibers. A layer of aluminum is sputtered on the sample to cover the PVP nanofibers as well as the SU-8 microstructures. Core-shell nanofibers are thus formed, where PVP nanofiber serves as the core and sputtered aluminum serves as the shell. The diameters of the core-shell nanofibers can be precisely controlled by the thickness of the sputtered aluminum layer. SEM images show the diameter of the base PVP nanofiber is about 175 nm. The diameters of the resulting core-shell nanofibers are 365 nm, 579 nm and 771 nm, respectively, after sputtering aluminum with 100 nm, 200 nm and 300 nm thick.After fabrication of core-shell nanofibers, the polydimethylsiloxane (PDMS) prepolymer (mixed at the weight ratio of 1:10) is poured on the sample and cured at 65 degreeC for 1 hour. The PDMS substrate is then peel off the SU-8 substrate. Since the core-shell nanofibers are embedded in the PDMS substrate, the nanofibers on the SU-8 microstructures rupture during peeling off, exposing the PVP materials. The PDMS substrate is then immersed in NaOH solution to remove the core-shell nanofibers. Nanochannels with the length-to-diameter ratio on the order of 100 or greater are thus formed. The formation of nanofluidic channels with a round cross-section is confirmed by perfusing Esosin Y dye into the nanochannels and examining the channels using optical microscopy. Nanochannel formation is also confirmed by scanning electron microscopy. This reported method allows a simple and reliable way for fabricating nanofluidic channels with controllable cross-sectional dimensions. The use of core-shell nanofibers as sacrificial molds not only provides easy access of nanofibers after peeling off, but also allows the use of various nanofiber materials that are intermiscible with the solvent used in soft lithography. In addition, the nanofiber diameter, the most important parameter that affects the performance of nano liquid chromatography and nano capillary electrophoresis, can be precisely controlled by sputtering.
9:00 PM - QQ6.14
Microfluidic Preparation of Polymersomes in Polymersome Structures Using Multiple Emulsion Droplets.
Shin-Hyun Kim 1 , Ho Cheung Shum 1 , Jin-Woong Kim 2 , David Weitz 1
1 School of Engineering and Applied Sciences and Department of Physics, Harvard University, Cambridge, Massachusetts, United States, 2 , Amore-Pacific Co. R&D Center, Yongin, Gyeonggi, Korea (the Republic of)
Show AbstractRecent advances in microfluidics enable to design and produce the droplets with unprecedentedly controlled manners. In particular, double emulsions produced in microfluidic device have been employed as templates for various microcapsules which are potentially useful in various applications, ranging from drug delivery, cosmetics, and foods to emerging areas of display devices and medicines. Through the polymerization or evaporation-induced consolidation of the middle phase in double emulsions, polymeric or inorganic microcapsules with controlled permeability have been prepared.In the present work, we report the microfluidic preparation of double polymersome structures, inner polymersomes encapsulated with outer polymersome, where the membrane is composed of biocompatible block copolymer bilayer of poly (ethylene-glycol)-b-polylactic acid (PEG-b-PLA). When the mixture of chloroform and hexane containing the diblock copolymers was emulsified to middle phase of water-in-oil-in-water (W/O/W) double emulsion droplets, the middle phase dewetted on the interface of inner water droplets as chloroform evaporates, resulting in polymersomes of single bilayer membrane. In order to produce polymersomes in polymersome structures, we produced quadruple emulsion droplets of W/O/W/O/W as templates by using coaxial glass capillary device. The device was comprised of two connected double emulsion makers based on flow-focusing geometry, and two-step sequential emulsifications enabled to produce quadruple emulsion droplets in relatively simple and efficient manner. The dewetting and evaporation of volatile oil in second and fourth phases created inner and outer bilayer membranes, respectively, which enabled to encapsulate two different materials in inner and outer polymersomes without mix and loss. Of particular interest in this context is that the capsulated materials can be released sequentially under external stimuli such as osmotic shock or mechanical force, owing to their multi-capsule structures. That is, the inner polymersomes have enhanced stability because the outer polymersome acts as a buffer. In addition, controlled rupturing of inner membrane enables to mix two capsulated materials within outer polymersome and the resulting mixture or products can be released at the desired moment. These separated encapsulation and sequential release properties have great potentials in delivery of drug or cosmetic-actives.
9:00 PM - QQ6.15
Optimizing Process Variables to Control Fiber Diameter of Electrospun Polycaprolactone Nanofiber Using Factorial Design.
Saida Khan 1 , Kadambari Bhasin 2 , Golam Newaz 1
1 Mechanical Engineering, Wayne State University, Detroit, Michigan, United States, 2 Biomedical Engineering, Wayne State University, Detroit, Michigan, United States
Show AbstractIn the electrospinning process, fibers ranging from 50 nm to 1000 nm or greater can be produced by applying an electric potential to a polymeric solution. In this study, the process parameters for the fabrication of electro-spun poly-caprolactone (PCL) nanofiber consisting of a range of fiber diameter (nm-um) have been investigated. PCL is a biocompatible, FDA approved and biodegradable polymer. As a solvent 2,2,2-trifluoroethanol (TFE) has been used for its biocompatibility, conductivity and high dielectric constant. The electrospinning technique consists of a simple setup with a number of variables working in a complex and unpredictable way. This study investigated the effects of polymer concentration in the solution, flow rate, applied voltage, tip to collector distance and diameter of the needle/capillary on fiber diameter. To optimize so many variables to control the fiber diameter, full factorial design method was used. Molecular weight and viscosity of the polymer solution are also found to be important parameters for the formation of the nanofibers. In the range of 3-5% concentration and voltage between 9-10kV, it was possible to produce uniform nanofiber with near 100 nm in diameter. The study is important for the fabrication of biomimetic scaffold for vascular implant and tissue engineering applications.
9:00 PM - QQ6.16
Development of Well-aligned Nanofibrous Membranes for Wound Healing.
Florencia Montini Ballarin 1 2 , Gustavo Abraham 2 , Patricia Frontini 2 , Shing-Chung Wong 1
1 Mechanical Engineering, University of Akron, Akron, Ohio, United States, 2 , Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA) (UNMdP-CONICET), Mar del Plata, Buenos Aires, Argentina
Show AbstractRecently, wound healing has gained much attention due to the development of novel materials in the nanoscale size with small pores, excellent pore-interconnectivity, very high specific surface area, great mechanical, and absorptive properties. The adhesion properties of wound dressings are important for future biomedical applications; in particular, for a good adhesion to the tissue that is healing and a reduced adhesion with time. Based on bioinspired dry adhesion of natural creatures, we developed a well-aligned nanofibrous membrane by electrospinning. The electrospinning setup consists of a tip collector (a wire grounded electrode inside a wooden board), a high voltage power supply, a nozzle, and a support plate. The influence of solution intrinsic properties and process parameters on the membrane morphology and properties was studied and optimized to produce aligned uniform bead-free fiber morphology. The adhesion properties of the membranes were measured by an adhesion peel test. The effect of the peeling rate and dwell time was studied. Some bulk and random nanofibrous membranes were prepared in order to compare the adhesion strength with the aligned ones. Morphological characterization of electrospun membranes, before and after testing, was carried out by Scanning Electron Microscopy (SEM).
9:00 PM - QQ6.17
Structure Control of Bioactive Titanate Nanomesh Layers Fabricated on Laser Irradiated Ti-based Bulk Metallic Glass using Hydrothermal-Electrochemical Method.
Sayaka Maruyama 1 , Naota Sugiyama 1 , Masahiro Yoshimura 2 , Togo Shinonaga 3 , Masahiro Tsukamoto 3 , Takeshi Wada 4 , Xinmin Wang 4 , Akihisa Inoue 4 , Kiyoshi Okada 1 , Nobuhiro Matsushita 1
1 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 2 Materials Science and Engineering, National Cheng Kung University, Tainan Taiwan, 3 Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka, Japan, 4 Institute of Materials Research, Tohoku University, Sendai, Miyagi, Japan
Show Abstract A series of Ti-based bulk metallic glasses (BMGs) have been studied extensively because of their excellent mechanical properties, i.e. low Young’s modulus, high elastic limit, high corrosion resistance and high abrasion resistance. They, however, contain toxic elements for the human body, such as Ni, Al and Be to enhance higher glass-forming ability. Recently, Ti-based BMGs with less toxic elements were developed for biomedical applications. However, they may not be directly joined to human bones because of their high chemical stability and bioinertness. The materials having bioactivity are, therefore, necessary between BMG and human bones. In previous study, we succeeded in giving bioactivity to the surface of Ti-based BMG (Ti40Zr10Cu36Pd14) by fabricating titanate nanomesh layers on it. In this study, Ti-based BMG was irradiated by the femtosecond laser to make the periodic micro groove on BMG surface before fabricating titanate nanomesh layers so that larger surface area could promote the growth of hydroxyapatite(HAp). The femtosecond laser with the laser wavelength of 775 nm, the pulse length of 150 fs and the repetition frequency 1 kHz was irradiated to BMG surface at the laser fluence of 1.0 J/cm2 in the spot diameter of 60 μm. The lens focus distance and sweep speed was 100 mm and 1.0 mm/sec, respectively. Titanate nanomesh layers were fabricated on the micro grooved BMG surface by hydrothermal–electrochemical (H-E) treatment. The BMG substrates were treated in a 0-5 mol/L NaOH aqueous solution at 90°C for 2 hours while a constant potential of 1.4-1.8 V was applied between the electrodes using water-cooled reference electrode (Ag/AgCl in 0.1 M KCl). The bioactivity of the samples was confirmed by soaking them in a conventional simulated body fluid (SBF) for 12 days. The H-E treatment in high concentration NaOH and applying low voltage enabled the faster growth of HAp.
9:00 PM - QQ6.19
Biomolecular Sensing Using Gold-coated ZnO Multipods.
Ramakrishna Podila 1 , Pengyu Chen 2 4 , Jason Reppert 4 , Apparao Rao 1 3 , Pu Chun Ke 1 2
1 Physics and Astronomy, Clemson University, Clemson, South Carolina, United States, 2 Laboratory of Single-Molecule Biophysics and Polymer Physics, Clemson University, Clemson, South Carolina, United States, 4 School of Materials Science and Engineering, Clemson University, Clemson, South Carolina, United States, 3 Center for Optical Materials Science and Engineering, Clemson University, Clemson, South Carolina, United States
Show AbstractGold nanoparticle-coated ZnO multipods have been utilized as a substrate for the detection of fluorescently labeled protein tetramethylrhodamine isothiocyanate bovine albumin (TRITC-BSA) and phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(Lissamine rhodamine B sulfonyl), or Rd-PE, down to the levels of 15 pM and 79 nM in aqueous solutions, respectively. When excited by light at 514 nm, surface plasmon polaritons were induced on the surfaces of the gold nanoparticles and converted to propagating photons by the scattering of the gold nanoparticles and the adsorbed biomolecular analytes. Electrostatic interactions were primarily accounted for the adsorption of the negatively charged moieties of the TRITC-BSA or the Rd-PE onto the positively charged ZnO multipod branches at neutral pH. The differences in morphology, molecular weight and amphiphilicity were attributed to the contrasting detection sensitivities for the two biomolecular species. Using simulations we further calculated the optical near fields for gold nanoparticle-coated ZnO tripod and tetrapod illuminated with a TM-polarized plane wave, showing the advantages of using multipods for biosensing.
9:00 PM - QQ6.2
Assembly of Vascularized Cell-Encapsulated Hydrogel Matrix Using a Stereolithography (SLA).
Jae Hyun Jeong 1 , Vincent Chan 2 , Chaenyung Cha 1 , Pinar Zorlutuna 2 , Rashid Bashir 2 , Hyunjoon Kong 1
1 Chemical and Biomolecular, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States, 2 Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show AbstractHydrogels are increasingly being used as cell encapsulation devices for both fundamental biology studies and cell transplantation therapies because of their structural similarity to the natural extracellular matrix. The successful use of a hydrogel in these biological applications relies greatly on the hydrogel permeability because it significantly affects the viability and function of cells. We hypothesized that incorporating interconnected micro-sized channels into a cell-encapsulating hydrogel would significantly improve the cell viability, depending on the spacing between micro-sized channels. In addition, increasing the diameter of the nano-sized pores in the hydrogel bulk was hypothesized to further elevate the fraction of viable cells.Our hypothesis was examined by combining a hydrogel formulation to control the diameter of the nano-sized pores over a broad range with a stereolithography apparatus (SLA) to control the micro-sized channels. The hydrogel consisted of poly(ethylene glycol) diacrylates (PEGDA) and methacrylic alginate (MA), so the hydrogel pore diameter was increased with mass fraction of MA while increasing elastic modulus in an independent manner. In this study, fibroblasts were encapsulated into the vascularized 3D hydrogel by the SLA based in situ photo cross-linking reaction. The role of micro-sized channels by combining a hydrogel formulation in enhancing cell-viability and regulating cell-functions was investigated. Further, the roles of incorporation of MA and microchannels in regulating fibroblasts function to secret proangiogenic growth factors and subsequently promote the neovascularization in a connective tissue was evaluated using chorioallantoic membrane (CAM). Implantation of PEGDA-1000 hydrogel onto CAM stimulated inflammation within two days likely because of extravasation of dead cells’ debris. In contrast, the PEGDA-1000/MA hydrogel minimally stimulated host inflammation likely because of its ability to let the encapsulated cells remain viable. Interestingly, fibroblast-encapsulated PEGDA-1000/MA containing microchannels increased the density of mature capillaries which present smooth muscle layers. Taken together, the results of this study will be an invaluable paradigm of a 3D cell encapsulation device prepared with a broad array of gel-forming polymers.
9:00 PM - QQ6.20
A Novel Platinum Nanowire Coating on Neural Electrode and its Impedance Characterization.
Young-Hyun Jin 1 , Patrick Daubinger 1 , Thomas Stieglitz 1
1 IMTEK, University of Freiburg, Freiburg Germany
Show AbstractWe introduced and characterized novel platinum nanowires as a coating material for low-impedance neural electrodes. In the field of neural recording and stimulation, not only considerable spatial resolution but also low electrical impedance is an important quality factor. Thus, use of porous materials such as iridium oxide, or surface coating to enlarge effective area e.g. platinum-black, is mandatory for micro neural electrodes. Recently nanowires have received attention as a coating material on neural electrodes. Some groups have reported electrodes coated with carbon nanotubes (CNTs). CNTs, however, generally need high temperatures for the synthesis process, which are not applicable to polymer electrodes.In this paper, a novel wet-chemical process, reported by Sun et. al. in 2008, has been introduced to synthesize platinum nanowires on neural electrodes. The synthesis was carried out at room temperature, confirming that it is suitable for polymer electrodes.The electrodes used in the present study were made of 400nm-thick platinum, sandwiched between two 5µm-thick polyimide insulation layers. The fabrication process was carried out using standard cleanroom processes. For nanowire coating, the fabricated electrode was floated on an aqueous solution, composed of 0.14 M-% chloroplatin acid hexahydrate and 7.4 M-% formic acid.First, the effect of process parameters on nanowire formation was evaluated. The nanowires on the electrode could be effectively modulated in terms of density and aspect ratio. The density of nanowires increased as process time progressed. As temperature increased, surface roughness was increased. A higher concentration of precursor resulted in a higher aspect ratio of the nanowires, but the nanowires covered polyimide as well as platinum. Based on the results, 3 process conditions were chosen as shown in the table. In terms of electrical characterization, the impedances of the electrode before and after the nanowire coating were compared. We observed that the impedance, especially at low frequencies, was significantly reduced. The cut-off frequency was reduced by up to 3 orders of magnitude. Using an equivalent circuit model and numerical fitting, we found that the effective electrode surface could be increased by up to a factor of 600 compared to a bare platinum surface. The strong adhesion of the nanowires has been confirmed by the observation of minimal structural changes after exposure of the samples to mechanical stress. In conclusion, the novel and facile platinum nanowire coating demonstrates a great potential for biomedical applications.
9:00 PM - QQ6.21
Protein Detection using Thermally-Reduced Graphene Oxide and Gold Nanoparticle-antibody Composites.
Shun Mao 1 , Ganhua Lu 1 , Kehan Yu 1 , Zheng Bo 1 , Junhong Chen 1
1 Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States
Show AbstractGraphene, a single layer of carbon atoms in a two-dimensional honeycomb lattice, has potential applications in the electrical detection of biological species due to their unique physical properties. Due to the high carrier mobility and large specific surface area of graphene, it is expected that graphene-based field effect transistor (FET) could to be applied in the electrical detection of biomolecules with extremely low detection limit. We report on a highly sensitive and selective FET biosensor using thermally-reduced graphene oxide (TRGO) sheet functionalized with gold nanoparticle (NP)-antibody conjugates. GO sheets are synthesized from purified natural graphite by a modified Hummers method and thermally reduced under high temperature in argon. Probe antibody (anti-Immunoglobulin G) is labeled on the surface of TRGO sheet through Au NPs and electrical detection of protein binding (Immunoglobulin G/IgG and anti-Immunoglobulin G/anti-IgG) is accomplished by FET and direct current (dc) measurements. The protein binding events induce significant change in the resistance of the TRGO sheet, which is referred to as the sensor response. The novel biosensor exhibits a detection limit of 2 ng/ml (~13 pM), which is among the best of carbon nanomaterial (e.g., carbon nanotube, graphene, GO)-based protein sensors. This hybrid nanomaterial-based biosensing platform can be designed to target various biomolecules by functionalizing TRGO with desired Au nanoparticle-antibody conjugates, which makes it potentially capable of detecting a variety of biomolecules for in vitro diagnostics.
9:00 PM - QQ6.22
Carboxy SNARF-1 Nanoreactors as a Selective pH Nano-sensor in Biological Media.
Yen-Chi Chen 1 , Agnes Ostafin 1 , Hiroshi Mizukami 2 3
1 Materials Science and Engineering, University of Utah, Salt Lake City, Utah, United States, 2 Biological Sciences, Wayne State University, Detroit, Michigan, United States, 3 , Nanoshell Company, LLC, Layton, Utah, United States
Show AbstractA nanoreactor with dual-wavelength fluorescence function for pH detection is developed in this project. The pH nano-sensor is made with calcium phosphate coated phosphatidylcholine liposomes with encapsulation of carboxy-SNARF-1 (cSNARF-1) dye. Particles mean size was analyzed to be 150 nm in diameter by using transmission electron microscopy and dynamic light scattering. Comparative analyses of fluorescence pH titration were performed with pH nano-sensor and pure dye carried out in water, and in the presence of the plasma, albumin and IgG The results show that the dye encapsulated nanoreactor minimized the serious distortions of the pH titration plots in the presence of albumin and plasma. The modified Henderson-Hasselbach equation was used to estimate the pKa values of the pure dye and dye encapsulated nanoreactor in different solution. The results indicate that when the dye encapsulated in nanoreactor, pH values were stable over time, photobleaching resistant, and reproducible under cyclic pH changes. The stopped flow fluorometric device was used to measure pH response time of dye encapsulated nanoreactor and revealed less than 200 msec. The fluorescence microscope was used to observe the particles and detect their colorimetric response in reference to the pH change. The observation also shows pH nano-sensor particles can maintain it integrity under continuous illumination up to 80 min. The dual-wavelength fluorescence dye encapsulated in nanoreactor shows a quick pH measurement, the shell coating provided the protection and extended pH range sensor ideal for use in biological system, microfluidics device and other complicate micro/nano environments.
9:00 PM - QQ6.24
Nanostructured Platinum Coated Carbon Nanotube Caterpillars as Electrochemical Biosensors.
Jonathan Claussen 1 , Scott Vander Laan 1 , Robert Sayer 1 , Timothy Fisher 1 , D. Porterfield 1
1 , Purdue University, West Lafayette, Indiana, United States
Show AbstractMonitoring biomolecules at low concentrations is vital to the diagnosis and treatment of diseases and to fundamental physiological research. Carbon nanotubes (CNTs) and metallic nanoparticles have increased sensitivity in enzymatic, nucleic acid, and cancer marker biosensors and immunosensors. Herein we develop electrochemical biosensors comprised of networks of nanostructured metallic nanoparticles connected via single-walled carbon nanotubes (SWCNTs). These networks are fabricated using a porous anodic alumina (PAA) template, created by anodizing a thin film metal stack comprised of a 2nm thick Fe layer sandwiched within a 400 nm thick Al layer e-beam evaporated on a Ti coated oxidized silicon wafer. The SWCNTs are subsequently grown from the imbedded Fe layer through a microwave plasma chemical vapor deposition (MPCVD) process. Multi-faceted Pt caterpillar nanostructures are electrodeposited onto the SWCNTs through a sequential pulsed current deposition technique. We can control the shape, size, and density of the Pt nanoparticles by varying the electrodepotion current, time, and metal salt concentration. By manipulating the nanoenvironment of the biosensor surface, we demonstrate the ability to program the sensitivity and detection limit of the biosensor. Thus we can tailor the performance of the biosensor for specific sensing applications. Varying concentrations of glucose, glutamate, and ethanol are amperometrically sensed by monitoring the oxidation of hydrogen peroxide, by biofunctionalizing the nanostructured sensor surfaces with the respective oxidase enzymes. The exemplary biosensor performance combined with the scalable in situ fabrication protocol make them well-suited for integration into commercial biosensors.
9:00 PM - QQ6.25
Metallic Nanoparticle on Micro Ring Resonator for Bio Optical Detection and Sensing.
Ali Haddadpour 1 2 , Yasha Yi 1
1 , NYU and CUNY, New York, New York, United States, 2 , Faculty of Electrical and Computer Engineering University of Tabriz, Tabriz Iran (the Islamic Republic of)
Show AbstractWe have numerically investigated the unique effects of metallic nanoparticle on the ring resonator, especially multiple Au nanoparticles on the micro ring resonator with the 4-port configuration on chip. For the Au nanoparticle, because it has smaller real refractive index than air and large absorption refractive index, we found that there is a blue shift for the ring resonance wavelength, instead of red shift normally observed for dielectric nanoparticles. The drop port intensity is strongly dependent on both number and size of nanoparticles, while relatively independent on position of nanoparticles. The correlation between the penetration depth of Au and the resonance mode evanescent tail is also discussed to reveal the unique properties of Au nanoparticle to be used for detection, sensing and nano medicine.
9:00 PM - QQ6.26
Nanoparticle-supported Molecular Brush.
Agnes Ostafin 1 , Chang-won Lee 2
1 Materials Science and Engineering, University of Utah, Salt Lake City, Utah, United States, 2 Bioengineering, University of Utah, Salt Lake City, Utah, United States
Show AbstractA gold nanoparticle-based pH sensor utilizing the mechanism of molecular monolayer brush collapse has been described. In this material, a bifunctional molecular ligand containing thiol and carboxylic acid functional groups forms a collapsible molecular brush on the surface of ~2 nm diameter gold nanoparticles. The thiol-based linkage creates a polarity sensitive photoluminescent charge transfer complex at the particle periphery. When a pH change eliminates the charge on the carboxylic acid, van der waals interactions lead to collapse of the ligands and the photoluminescent species responds to the change in local polarity. Electron microscopy, electrophoresis, dynamic light scattering and mass spectrometry were used to characterize the materials. Absorption, fluorescence emission and excitation, and zeta potential measurements were used to understand the reversible pH response, and a model for the interactions between ligand complexes and the gold nanoparticles is discussed. This material can be used as a pH sensor with an operational range between pH 5 and 8.
9:00 PM - QQ6.27
Infrared Plasmonic Metamaterials for Biosensing using a Quantum Cascade Laser.
Alket Mertiri 2 , Kai Chen 3 , Ronen Adato 3 5 , Ahmet Ali Yanik 3 , Mi Hong 1 , Hatice Altug 3 5 2 , Shyamsunder Erramilli 1 2 4
2 Division of Materials Science and Engineering, Boston University, Boston, Massachusetts, United States, 3 Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts, United States, 5 Photonics Center, Boston University, Boston, Massachusetts, United States, 1 Physics, Boston University, Boston, Massachusetts, United States, 4 Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States
Show AbstractPlasmonic Metamaterials can be engineered for functional studies on monolayers of proteins and other biomolecules. Informed by extensive numerical simulations, electron beam lithography is used to fabricate nanostructures that enhance selected vibrational infrared “fingerprint” modes of biomolecules. Fourier Transform Infrared Microscopy using a broadband 1200 K Globar source shows sensitivity for protein molecules at the attomole level. Tunable Infrared Quantum Cascade Laser (QCL) has a spectral brightness more than 10^5 greater than the Globar blackbody source and >10^2 greater than mid-infrared synchrotron radiation. It promises to provide unprecedented sensitivity when combined with engineered plasmonic metamaterials. A home-built IR microscope is used in combination with a tunable QCL, a plasmonic substrate and lock-in detection to measure the sensitivity and specificity of performing vibrational infrared spectroscopy on biomolecules. The potential for the system to perform mid-infrared measurements in water is discussed. Of particular interest is that applying phase matching the plasmonic substrate may be used in water without the need of Attenuated Total Reflection (ATR) geometry. Support from DOD and NSF-DMR is gratefully acknowledged. We thank Dr Thomas Jeys, MIT Lincoln Labs for discussions.
9:00 PM - QQ6.28
Uniform and Controllable Preparation of Au-Ag Core-Shell Nanorods.
Yasuro Niidome 1 , Ayaka Kiya 1 , Yuki Nakamura 1 , Naotoshi Nakashima 1
1 , Kyushu University, Fukuoka Japan
Show AbstractGold nanorods were wrapped with silver shells to obtain uniform anisotropic nanoparticles that showed the spectroscopic characteristics of silver. The gold nanorods are uniform rod-shaped gold nanoparticles that show distinct optical characteristics originating from their anisotropic shapes. Formation of uniform silver shells on gold nanorods has been expected to be a useful method to prepare uniform anisotropic silver nanoparticles.
The silver shell formation on gold nanorods in a micellar solution of hexadecytrimethylammonium chloride was rapid. Uniform Au-Ag core-shell nanorods were obtained by retarding the silver shell growth on gold nanorods. TEM observations indicated that the growth of the silver shells was anisotropic; the silver shells in the transverse direction were thicker than that in the longitudinal direction. The colloidal solutions of the Au-Ag core-shell nanorods showed four extinction bands that were originated from the anisotropic silver shells. The spectroscopic characters and the TEM images of the core-shell nanorods indicated that our methods gave very reproducible and controllable core-shell nanorods.
The ability to manipulate the shapes and sizes of these nanoparticles offers a wide-range control of the surface extinction from the visible to the near infrared regions (450−800 nm). The monodisperse anisotropic silver nanoparticles will be a novel probe material for biosensing and bioimaging.
Y. Okuno, K. Nishioka, A. Kiya, N. Nakashima, A. Ishibashi, and Y. Niidome, Nanoscale, in press.
9:00 PM - QQ6.29
ZnO Nanowire Devices Based on Novel Functionalization Platform for Chemical and Biological Applications.
Jintae Kim 1 , Rizwan Khan 1 , Hyun-Wook Ra 1 , Bora Kang 1 , Deepti Sharma 1 , Yeon Ho Im 1
1 Chemical Engineering, Chonbuk National University, Jeonju Korea (the Republic of)
Show AbstractZnO nanowires are regarded as one of the promising candidates for high performance biosensor applications due to their unique properties. To achieve this goal, robust bio-molecule immobilization on ZnO nanowires surface with high solution stabilities still remain a great challenge for chemical and biological sensor applications. In this work, we present systematic comparative studies of functionalization methods including covalent bonding with the silane based modifier and surface polymerization with plasma. ZnO nanowire devices with the optimized functionalization methods were successfully demonstrated for the pH sensing, and the label free detection of various bio-molecules such as streptavidin/avidin, and Hepatocellular Carcinoma (HCC) markers. To verify our approaches, the bio-molecule immobilized surfaces of ZnO nanowires were investigated using fluorescence microscopy and field effect transistor (FET) with electrolyte gate configuration. Furthermore, it was found that the long time stabilities of the nanowire devices under acidic or basic solution can be drastically improved as compared to the pristine ZnO nanowires. Finally, the HCC antibody immobilized nanowire devices were shown to be capable of highly selective and sensitive detection of HCC antigen in the serum of liver carcinoma patient.
9:00 PM - QQ6.3
Patterned CaTiO3 Nanostructures Prepared by Two-step Anodization-hydrothermal Method.
Chun-Yi Chen 1 2 , Kazunari Ozasa 1 2 , Kenichi Katsumata 1 , Kiyoshi Okada 1 , Nobuhiro Matsushita 1
1 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama Japan, 2 Advanced Science Institute, RIKEN, Wako Japan
Show AbstractIn recent years, perovskite oxides have drawn much interest due to their unique dielectric, piezoelectric, ferroelectric, photocatalytic, and bioactive properties, and they have been widely applied in many fields. Synthesis strategy of perovskite oxide nanostructures usually involves application of porous templates, such as anodic alumina oxide and silica porous templates. Morphology of nanoarrays can be controlled by structure of the template and aggregation occured during thermal treatment can be avoided when porous template is used. However, removal of the template without destroying perovskite oxide nanostructures is a critical issue when porous template is used. Among perovskite oxides that have been studied recently, synthesis and properties of CaTiO3 are rarely studied. In addition, the synthesizing process of CaTiO3 nanostructures by using a low temperature solution process has not been reported in detail.Herein we report a novel synthesizing method of patterned CaTiO3 nanostructure by using two-step anodization-hydrothermal method. TiO2 nanotubes array was prepared at 20V for 15h in glycerol electrolyte with 0.5% NH4F, and they were used as the precursor of CaTiO3 nanostructure. Diameter of individual TiO2 nanotube was ca. 50nm, and tube length was ca. 3μm. The hydrothermal reaction was performed in saturated Ca(OH)2 solution at 150-200°C, and transformation in composition and morphology was observed when experimental time was increased from 2 to 12h. SEM images revealed that, CaTiO3 nanostructures were 45~75nm in width and 25-275nm in length. CaTiO3 nanostructures which connected each other can be expected to reinforce the mechanical property. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were employed to characterize the structure, composition, and chemical state of CaTiO3 nanostructures. Hydrophilicity was also studied to evaluate the biocompatibility of CaTiO3 nanostructures. In summary, we successfully prepared patterned CaTiO3 nanostructure which has the potential for induction and inhibition of hydroxyapatite formation due to its engineered surfaces.
9:00 PM - QQ6.30
Preparation and Characterization of Thin Polyaniline / poly (ethenesulfonic acid) Films with Potential Application in Diagnosis of Uremia.
Felipe Teixeira 1 , Rodrigo Bianchi 1
1 Department of Physics, Federal University of Ouro Preto, Ouro Preto, MG, Brazil
Show AbstractThe Uremia is a metabolic syndrome consisting of sharp increase in urea concentration in the systemic circulation disorders characterized by biochemical, clinical signs and extrarenal lesions. The term uremia, which literally means urine in the blood, was first used by Piorry to describe the clinical condition associated with renal failure. Uremia more commonly develops with chronic renal failure (CRF) or the later stages of chronic kidney disease (CKD), but it also may occur with acute renal failure (ARF) if loss of renal function is rapid. In this syndrome may be heralded by the clinical onset of nausea, vomiting, fatigue, anorexia, weight loss, muscle cramps, pruritus, and change in mental status. Tests to measure the amount of urea in the blood (BUN) can be used as an indicator of renal function and occurrence of uremia (a disease that accompanies kidney failure), but few methods have been developed for the purpose of determining the concentration of urea in the blood. The existing methods such as enzyme systems based on immobilization of urease activity, are composed of steps laborious, time consuming and require skilled labor to biologists and biomedical. In this context the detection of biologics such as industrial ammonia and nitrogen compounds (i.e. urea and creatinine) in the blood and in the urine is important to human health and safety. However, urea concentrations in the blood to diagnose uremia are levels above of 60 mg/dl and highly sensitive and selective sensors are needed. Thus, the development of biologic sensors with high sensitivity, high selectivity, and rapid detection is essential and could impact human beings in significant ways. In this work we investigated the optical properties of nanostructured films of PANI / PVS deposited on glass substrate by the technique Layer-by-layer to be applied as organic sensors to detect concentrations of urea in the bloodstream. These films of low production cost and easy handling were exposed to different concentrations of aqueous urea (< 100 mg/dl), and characterized by UV-VIS absorption measurements. The results show that PANI was deprotonated and its color shifts from green to blue when exposed to urea. It is a basic principle operation of a novel urea sensor based on polyaniline system. This work was sponsored by Capes, CNPq, Nanobiomed/Capes, INEO/CNPq and Fapemig.
9:00 PM - QQ6.31
Nanometric Ion Sensing Using Near-field Ratiometric Fluorescence Sensing.
Ella Wajnryt 1 , Aaron Lewis 1 , Patricia Hamra 2 , Chaya Lewis 2
1 Department of Applied Physics, The Hebrew University of Jerusalem , Jerusalem Israel, 2 , Nanonics Imaging Ltd, Jerusalem Israel
Show AbstractA nanometric measurement of ionic concentrations at distances extending from nanometers to microns from a charged surface immersed in solution is described. AFM and NSOM techniques were combined using NSOM’s nanometric light confinement abilities for optical pH sensing. AFM allowed for knowledge/control of the distance between the optical pH-meter and investigated surface. A ratiometric method of fluorescence sensing was used. A pH sensing fluorescent dye, i.e. fluorescein was complexed to a non-pH sensing dye, rhodamine through a dextran molecule and thus the concentration of dye molecules were equivalent in each nanometric solution volume element. The results profile the nanometric variation in pH as a function of distance from such a charged surface. The approach has great potential to accurately monitor charge distribution in solutions and in close proximity to all surfaces. The measurements provide important experimental underpinnings to long established solution structure theories, eg. those of Debye and Gouy-Chapman
9:00 PM - QQ6.32
Template Fabrication of a Nanoporous Polycaprolactone Thin-film for Retinal Tissue Engineering.
Kevin McHugh 1 2 , Magali Saint-Geniez 3 , Sarah Tao 1
1 , The Charles Stark Draper Laboratory, Inc., Cambridge, Massachusetts, United States, 2 Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States, 3 Schepens Eye Research Institute and the Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
Show AbstractAge-related macular degeneration (AMD) is the leading cause of blindness in developed countries for people over 55 of age. AMD is a complex and multi-factorial disease described as two distinct types, dry and wet, both of which currently lack ideal therapeutic treatments. Abnormalities in the retinal pigment epithelium (RPE) and underlying Bruch’s membrane are central to the development of AMD leading to vision loss. In this research, a nanoporous poly(e-caprolactone) (PCL) thin film (approximately 5 μm) was fabricated to serve as an implantable, biodegradable Bruch’s membrane prosthesis for tissue engineering RPE as a potential treatment for AMD. Regularly spaced conical and cylindrical features were fabricated in silicon with diameters less than 500 nanometers and with exceptional yield using standard microelectomechanical systems (MEMS) techniques. The height, aspect ratio, and packing of features were easily controlled by modifying photomask design and dry etch parameters. A spin-assisted templating method was then used to transfer the inverse nanostructures into PCL, creating a nanoporous thin-film to serve as an artificial Bruch’s membrane. The membrane properties including thickness, pore size, porosity, electrical resistivity, and molecular transport were designed based on the physiological requirements for sub-retinal tissue transplantation. It was further demonstrated that these novel PCL thin-films enhance RPE polarization, differentiation, and maturation. It is shown here that the use of MEMS techniques, together with polymer nanotemplating, results in a highly-uniform, reproducible scaffold which exposes cells to identical physical cues. This technique allows for substantial control of individual discrete nanoscale features making it potentially superior to alternatives such as electrospinning which yield highly variable and irregular features that disrupt RPE maturation and tight junction formation. By providing control over nanofeature resolution, consistency, and yield MEMS techniques allow for the fabrication of tunable scaffolds that provide RPE with an artificial microenvironment conducive to physiologically appropriate tissue formation. This MEMS-based approach to tissue engineering is therefore a promising strategy for the treatment of retinal degenerative disease such as AMD. Copyright © 2010 by The Charles Stark Draper Laboratory, Inc. all rights reserved.
9:00 PM - QQ6.33
Conductivity and Compatibility of Poly-lactic-co-glycolic Acid Carbon Nanofiber Material for Cardiomyocytes.
David Stout 1 , Thomas Webster 1 2
1 Division of Engineering, Brown University, Providence, Rhode Island, United States, 2 Department of Orthopedics, Brown University, Providence, Rhode Island, United States
Show AbstractIn recent years poly-lactic-co-glycolic acid (PLGA) has been under investigation for myocardial tissue engineering due to its ability to be Food and Drug Administration (FDA) approved for therapeutic devices because of its biodegradable and biocompatible tendencies. It has also been shown that Carbon Nanofibers (CNFs) assist and strengthens materials when added to biological mixtures. To see if a compatibility between PLGA and CNF’s for myocardial tissue engineering, different PLGA:CNFs ratios (100:0, 75:25, 50:50, 25:75, 0:100) were created and arranged onto a glass substrate to determine conductivity and sustainability. Next, human cardiomyocytes (Celprogen cat#36044-15) were transplanted onto the different PLGA:CNF ratio materials to determine cell compatibility. Results show that PLGA:CNF materials do have conductivity characteristics which increase in conductivity as more CNF is added. SEM imaging was used to show the visual characteristics between the different PLGA:CNF ratio materials and also human cardiomyocyte compatibility. Results indicate that PLGA:CNF material would be a novel biomaterial for myocardial tissue engineering due to its biodegradability and conductivity, thus providing an alternative medium for cardiomyocyte implantation for a cardiovascular patch.
9:00 PM - QQ6.34
Electrical Characteristics of Poly(ethylene oxide)-urea Complex for Urea Biosensing.
Mi Yeon Cho 1 , Kyoungah Cho 1 , Sangsig Kim 1
1 Electrical Engineering, Korea University, Seoul Korea (the Republic of)
Show AbstractIn this study, poly(ethylene oxide) (PEO)-urea complex films were prepared and the electrical characteristics were investigated for the appliaction of urea biosensing. The complex films made of a mixture of PEO and urea were spin-coated with various concentrations of urea on glass. First of all, XRD patterns were taken from the PEO-urea complex films to examine the structural characteristics. In the PEO-urea complex films, two different crystalline structures were observed in the XRD patterns, and furthermore our X-ray study revealed that the crystallinity of the complex films was enhanced with increasing concentration of urea; additionally, the morphology of the PEO-urea complex films were also checked through scanning electron microscope (SEM) as well as optical microscope. Electrical characteristics of the PEO-urea complex films were examined and analyzed as a fuction of the concentraion of urea while comparing the structural characteristics. The electrical conductivity of PEO-urea complex films was improved with increasing concentration of urea due to the enhanced crystallinity of the complex film. The same improvement in the electrical conductivity was observed for PEO-urea complex films obtained by dropping urea solution with various concentraions on PEO films. Our study suggests the promising possibility that PEO-urea complex films can be used as active layers of urea biosensors.
9:00 PM - QQ6.35
Highly Sensitive Plastic Based FET Biosensors.
Sangyong Lee 1 , Seungjun Kim 1 , Teajung Park 1 , Keonjae Lee 1
1 , KAIST, Deajeon Korea (the Republic of)
Show AbstractPoint of care testing(POCT) are being studied with great interest for disease diagnosis such as complete blood count, routine chemistry test, glucose concentration, cancer, DNA and viruses. Essential elements of biosensor that suitable for POCT are portable, simple, highly sensitivity, rapid and real time detection. Considerable researches for biosensor such as surface plasmon resonance(SPR), enzyme-linked immunosorbent assay(ELISA), micro-cantilevers, surface-enhanced spectroscopies, and optical devices have been performed significantly over last decades. Each of these methods, however, has yet demonstrated the combination of POCT features such as label free, highly sensitivity, simple, quick and real-time detection of biomolecules. Field effect transistor (FET) type biosensors1) offer opportunities to develop suitable for POCT by overcoming the deficiencies of above mentioned approaches. Regardless of these merits, FET type biosensors have limit of applications because they are fabricated on non biocompatible, brittle and expensive substrates such as Silicon or SOI wafers. Rogers and coworkers reported microstructured semiconductors (μs-Sc) technologies for the high performance flexible electronics by transferring ultrathin single crystal Si ribbons onto plastic substrates by using standard microfabrication and soft lithographic printing technique.2) Herein, we report highly sensitive FET biosensors utilizing single crystal μs-Si transistors and non-surface-modified silica binding protein(SBP) immobilization3) were fabricated on plastic substrates combined with microfluidic technologies for detecting bioreceptor molecule of avian influenza(AI) antigen. From the results, we demonstrate plastic based FET biosensors suitable for POCT and substrate-free bio-implantable applications.Reference1) E. Stren et. al., Label-free immunodetectionwith CMOS-compatible semiconducting nanowires, nature, 2007, 445, 519 2) K.J Lee et. al., Large area, selective transfer of microstructured silicon : A printing-based approach to high performance thin film transistors supported on flexible substrates, Adv. Mater., 2005, 17, 2332 3) B.S Gu, T.J Park et. al., Nanogap field-effect transistor biosensors for electrical detection of avian influenza, Small, 2009, 5, 2407
9:00 PM - QQ6.4
Dissolvable Trimolybdate Nanowires and Their Unique Applications in Nanochannel Fabrication and Anti-bacterium Treatment.
Jiongwei Xue 1 , Xiudong Wu 1 , Yujie Jiang 1 , Qiangwei Zhuang 1 , Shengyong Xu 1
1 Key Laboratory for the Physics & Chemistry of Nanodevices, and Department of Electronics, Peking University, Beijing China
Show AbstractMicro-/nanochannel systems are important platforms for studies on biomaterial separation, localized catalysis and analytical chemistry, ion conductance, as well as microfluidics and nanofluidics. It is desirable to find a repeatable and rapid way to fabricate micro-/nanochannel systems with low cost and simple techniques. We show here that this goal can be realized by using water-dissolvable or ethanol-dissolvable trimolybdate nanowires together with in situ nano-probes and standard lithography techniques.We have found a very simple approach to synthesize well-shaped nanowires of two pure trimolybdates, K_2Mo_3O_10-3H_2O and Na(NH_4)Mo_3O_10-H_2O, and of one doped trimolybdate, (NH_4)_(2-x)Ag_xMo_3O_10. Among them, the first two kinds of nanowires are water-dissolvable, and the last is not dissolvable in water but in ethanol. The synthesis procedure for each kind of nanowires requires only mixing of two separate solutions accordingly, at a constant temperature between 0 deg. C and 90 deg. C in a water-bath and under one atmosphere. The time needed for a complete reaction is only in the order of 1-10 minutes. Analyses of X-ray diffraction, electron diffraction and thermogravimetric results all clearly reveal that each of these nanowires has a pure crystalline phase, respectively, matching well to its known bulk phase.A splitting-effect along longitudinal axis of these nanowires is observed in the dissolving process, which is subsequently found helpful in fabrication of nanochannels when these nanowires are embedded in a channel material as sacrificial templates and then are dissolved later. By choosing different lithography procedures, micro-/nanochannel systems with desired diameters, lengths and number of channels, with controllable cross-sectional shapes (e.g., round or hexagonal) and controllable channel materials (e.g., various oxides, metals and polymers), can be routinely fabricated at the pre-targeted locations. Measurements of ion conductance show that these micro-/nanochannel systems work well, showing typical ion conductance behaviors as theoretically expected.We have also found that Ag-doped (NH_4)_(2-x)Ag_xMo_3O_10 nanowires, where x~0.6, have remarkable anti-bacterium properties in inhibiting various bacteria. The minimum inhibition concentration (MIC) values are measured to be 100 ppm for both E.coli and Staphylococcus aureus. When an aqueous solution of 1% (NH_4)_(2-x)Ag_xMo_3O_10 is applied, the radii of inhibition zones for E.coli and Staphylococcus aureus are 3.0 mm and 2.0 mm, respectively.The results show that trimolybdate nanowires have a great potential for applications in such as nanochannel system, biochemistry and medicine.
9:00 PM - QQ6.5
Field Induced Nanolithography for Patterning Polymer Brushes.
Robert Ferris 1
1 Mechanical Engineeering and Material Science, Duke University, Durham, North Carolina, United States
Show AbstractWe present our research on patterning polymer brush surfaces with electric field induced nanolithography (FINL). Specifically, we demonstrate FINL patterning on non-fouling polyoligo(ethylene glycol) methyl methacrylate (POEGMA) brush surfaces, as an accessible technique for the fabrication of biomolecular detection nano-arrays. We show that FINL can produce nanoscale attachment sites on the brush surface that allow for covalent binding of aldehyde reactive biomolecules. We find that feature size depends on lithographic parameters including the tip bias voltage, exposure time, applied pressure, and ambient relative humidity. Our results show that the topographic feature dimensions are primarily determined by the size of the water meniscus formed about the AFM tip during patterning. Next to topographic features, FINL of POEGMA thin films also produce localized chemical modifications that can be used to control the attachment of biomolecules. Surface reactivity was studied and verified with X-ray Photoelectron Spectroscopy (XPS), non-contact scanning probe microscopy, and fluorescence spectrometry. Kelvin Probe Force Microscopy (KPFM) revealed a decrease in surface potential in areas patterned with a positive tip bias. Electric Force Microscopy (EFM) imaging showed that this decrease in surface potential was due to a localized decrease in electron charge density. We surmise that the change in film electronic structure is due to the disturbance of the oligo(ethylene glycol) side chain ordering. This is substantiated by XPS high resolution scans of the C1s region, which revealed the cathodic reduction of ester groups on the polymer brush surface. The reaction byproducts and their corresponding surface concentration were: carboxylic acid (1%), aldehyde (2%), and alcohol (7%) groups. Finally, surface reactivity was verified with micropattern FINL surfaces in two ways; first through exposure to Tollens reagent, and second through the covalent attachment of Alexa Fluor 488® aldehyde reactive fluorescent probes. Our work is the first demonstration of FINL for nano and micropatterning of polymer brush thin films, and demonstrates the potential of the method for facile chemical surface modifications on polymer brush thin films.
9:00 PM - QQ6.6
Heterogenous Nucleation of Lysozyme Crystals on Nanoporous Gold (NPG).
Felicitee Kertis 1 , Lata Govada 2 , Sahir Khurshid 2 , Naomi Chayen 2 , Jonah Erlebacher 1
1 Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States, 2 Division of Surgery, Oncology, Reproductive Biology and Anaesthetics, Imperial Collge, London United Kingdom
Show AbstractInducing proteins to nucleate crystals of high-enough quality for X-ray diffraction experiments is the major limiting step in protein crystallography. Most protein crystallization employs homogeneous nucleation, i.e., without any obvious substrate to induce the formation of crystals, but the supersaturations required to initiate nucleation often lead to low quality crystals. To address this concern, heterogeneous nucleation of protein crystals on random nanoporous substrates whose pore size is of the order of the protein size, has been proposed as a path to good crystallization at more moderate supersaturations because the entropic penalty associated with nucleation should be ameliorated. In this study we report the use of patterned substrates of dealloyed nanoporous gold (NPG) to promote the crystallization of the protein lysozyme in sitting-drop experiments, where NPG is a convenient porous material because it is inert and has a tunable pore and ligament size controllable from 5 nm to 1 micron. Overall, we show a strong variation of the heterogeneous nucleation rate with pore size and will discuss details of this variation with respect to temperature and supersaturation.
9:00 PM - QQ6.8
Reduced Resistance to Air Flow from Nanomodified Endotracheal Tubes.
Mary Machado 1 , Keiko Tarquinio 2 , Thomas Webster 1
1 , Brown University, Providence, Rhode Island, United States, 2 , Rhode Island Hospital, Providence, Rhode Island, United States
Show AbstractVentilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would help to prevent this problem. The objective of this study was to determine differences in bacterial growth on nanomodified and unmodified ETTs under dynamic airway conditionsThe ETTs tested in our system were polyvinyl chloride (PVC), with nano-roughened surfaces created by exposing PVC tubing (Sheridan ETT, Colvidien) to a 0.1% mass solution of lipase from the either the fungi C. cilindracea or R. arrhisus (Sigma Aldrich) dissolved in a potassium phosphate buffer. ETTs placed in the system were modified on both the inner and outer surfaces.A bench top model based upon the general design of Hartmann et al. (1999) was constructed to test of the effectiveness of nanomodified ETTs under the airflow conditions present in the airway. A sterilization run was performed for 24 hours prior to each use of the system to prevent cross contamination. Cuff pressure was monitored every twelve hours and the upper box was agitated for thirty minutes before each sample was taken. Colony counts were performed on samples taken from the lung box and oropharynx at the 12, and 24 hour time points. Twenty-four hour studies performed in the dynamic flow chamber showed a marked difference in the biofilm formation on different areas of unmodified tubes. Areas where tubes were curved, such as at the entrance to the mouth and the connection between the oropharynx and the larynx, seemed to collect the largest amount of biofilm. On the nanomodified tubes film formations were markedly different occurring in smaller pieces. The biofilm formation on ETT in the airflow system after 24 hours showed a large difference depending upon where tubes were oriented within the apparatus. This illustrates the importance of dynamic flow on biofilm formation in pediatric ETTs. It is of particular interest that increased biofilm density in both unmodified and nanomodified tubes appeared to occur at curves in the tube where changes in flow pattern occur. This emphasizes the need for more accurate models of airflow within pediatric ETT, suggesting that not only does flow effect pressure gradients along the tube, but in fact determines the composition of the film itself.More testing is needed to determine the effects of biofilm formation on the efficiency of ETT under airflow, however this study provides significant evidence for nanomodification alone (without the use of antibiotics) to decrease bacteria function.
Symposium Organizers
Larry A. Nagahara National Cancer Institute
Robert Sinclair Stanford University
Rashid Bashir University of Illinois, Urbana-Champaign
Thomas Thundat Oak Ridge National Laboratory
Wenbin Lin University of North Carolina, Chapel Hill
QQ7: Multifunctional Nanoparticles for Biomedical Applications
Session Chairs
Wenbin Lin
Larry Nagahara
Wednesday AM, December 01, 2010
Grand Ballroom (Sheraton)
9:00 AM - QQ7.1
Layer-by-layer Assembled Cysteamine - Gold / siRNA / PEI / HA Complex for Target Specific Gene Silencing Applications.
Min-Young Lee 1 , Sang-Joon Park 1 , Kitae Park 2 , Ki Su Kim 1 , Sei Kwang Hahn 1 2
1 Material Science & Engineering, POSTECH, Pohang Korea (the Republic of), 2 School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang Korea (the Republic of)
Show AbstractTarget specific intracellular delivery of small interfering RNA (siRNA) has been regarded as one of the most important technologies for the development of siRNA therapeutics. In this work, we successfully developed cysteamine modified gold (AuCM) / siRNA / polyethyleneimine (PEI) / hyaluronic acid (HA) complex using layer-by-layer method for target specific intracellular delivery of siRNA by HA receptor mediated endocytosis. Zeta potential and particle size analyses confirmed the formation of AuCM/siRNA/PEI/HA complex having a particle size of ca. 160 nm and a slightly negative surface charge. With negligible cytotoxicity, the AuCM/siRNA/PEI/HA complex showed an excellent target specific gene silencing efficiency higher than 70% in B16F1 tumor cells with HA receptors in the presence of 50 vol% serum. The target specific intracellular delivery of AuCM/siRNA/PEI/HA complex to B16F1 cells by HA receptor mediated endocytosis was clearly visualized by dark-field bioimaging. The novel AuCM/siRNA/PEI/HA complex, which can deliver siRNA specifically to the cells with HA receptors, will be investigated further for clinical applications.
9:15 AM - QQ7.2
Gene Silencing with Calcium Phosphate Nanoparticles Incorporated into Polyelectrolyte Multilayers.
Anna Kovtun 1 , Xin Zhang 2 3 , Nadia Benkirane-Jessel 2 3 , Matthias Epple 1
1 Inorganic Chemistry and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Essen Germany, 2 Faculté de Médecine, Institut National de la Santé et de la Recherche Médicale, Strasbourg Cedex France, 3 , Faculté de Chirurgie Dentaire de l’Université de Strasbourg, Strasbourg Cedex France
Show AbstractGene therapy is used for in situ modification of the protein expression. For this, the nucleic acids aimed at protein expression or gene silencing must be delivered into the cell. However, to obtain stably modified cells, the elevated concentration of nucleic acid must be maintained within the cellular microenvironment for some time without side effects on the rest of organism. In this work we represent a method for gradual and efficient gene silencing from the surfaces coated with polymers and shRNA-functionalized calcium phosphate nanoparticles. The coating was prepared by the layer-by-layer technique, and the efficiency of gene silencing was tested in the cell culture.The nanoparticles used for gene silencing were functionalized with shRNAs against osteopontin or osteocalcin. These proteins play a central role in the mineralization and the remodeling of bone, thus maintaining the calcium ion homeostasis. To provide further protection against nucleases and steric and electrostatic stability of the nanoparticles, the additional shells of calcium phosphate and shRNA were added onto the previously described single-shell particles. These systems were denoted as multi-shell particles.Both types of particles had a spherical shape and a diameter of 100 nm to 250 nm. shRNA-functionalized nanoparticles were effectively embedded into poly-L-lysine (PLL) multilayers and tested on human osteoblast cells.The expressions of proteins were inhibited both in the case of transfection from a dispersion as well as from the (PLL-nanoparticles)n multilayer films. However, the inhibition of osteopontin or osteocalcin expression from the films consisting of six bilayers was most efficient.
9:30 AM - **QQ7.3
Oligonucleotide-Gold Nanoparticle Conjugates as Probes for Intracellular Diagnostics and Gene Regulation.
Chad Mirkin 1
1 Chemistry, Northwestern University, Evanston, Illinois, United States
Show AbstractOligonucleotide-nanoparticle conjugates consist of a colloidal gold nanoparticle core, functionalized with a dense oligonucleotide monolayer. The nanoparticle conjugates display remarkable cooperative properties, such as enhanced target hybridization, high stability in biological environments, low immune response, and efficient uptake by cells due to their unique architecture. These properties make the oligonucleotide-nanoparticle conjugates ideal for many intracellular applications, including gene regulation and detection of target biomolecules. This talk will focus on the fundamental nanochemistry behind the biological properties of the oligonucleotide-gold nanoparticle conjugates and recent advances in their application towards therapeutic and diagnostic applications. Both in vitro and in vivo (animal data) will be discussed.
10:00 AM - QQ7.4
Targeted Multifunctional Magnetic Nanoparticles for Synergistic siRNA Delivery and Hyperthermia.
Prasad Subramaniam 1 , Joung Park 1 , Jongjin Jung 1 , Birju Shah 1 , Cheoljin Kim 1 , Jong Lee 2 , Jee Cho 3 , Chul Lee 3 , Ki-Bum Lee 1
1 Chemistry and Chemical Biology, Rutgers-The State University of New Jersey, Piscataway, New Jersey, United States, 2 Center for Nano-Bio Fusion Research, Korea Research Institute of Chemical Technology, Daejon Korea (the Republic of), 3 Center for Magnetic Resonance Imaging, Korea Basic Science Institute, Ochang Korea (the Republic of)
Show AbstractMagnetic nanomaterials have shown great potential for cancer research as non-invasive imaging probes as well as multifunctional therapeutics. For example, magnetic nanoparticles (MNPs) have been successfully used to deliver therapeutic biomolecules such as anti-cancer drugs, antibodies, and small interfering RNA (siRNAs) to the target tumor cells or tissues. In addition, their attractive magnetic properties enable their successful application in cancer research and therapy including magnetic resonance imaging (MRI) and hyperthermia. However, in spite of these merits, MNP-based cancer therapies have been slow to reach the clinic due to the lack of specificity and inaccessibility to the tumors. Hence, in order to realize their full potential in a clinical setting, there is an urgent need to synthesize effective chemotherapeutic magnetic nanoparticles and to develop multimodal therapies for targeting specific oncogenes thereby modulating the corresponding key signaling pathways in tumors.We focused on the synthesis of graphitic-carbon protected FeCo MNPs (FeCo/C NPs) using a novel hydrothermal approach, for the targeted delivery of siRNAs for sensitizing tumor cells to hyperthermia and for the selective knockdown of a key oncogene expressed and implicated in several cancers including brain and breast tumors. It is well known that hyperthermia and its downstream effects can be significantly enhanced by the concomitant use of other cancer therapies including radiation and drug/gene delivery and vice versa. Hence, we hypothesized that an integrated therapeutic system utilizing site-specific hyperthermia and siRNA delivery would result in synergistic effects on inhibiting the proliferation and inducing apoptosis of tumor cells.As a model for our studies, we used brain tumor cells (bTCs). Brain tumor is one of the most malignant and difficult-to-treat cancers, with a mean survival rate of 12 months. It was found that our FeCo/C NPs showed excellent MRI contrast, both in vitro and in vivo, compared to conventional MRI contrast agents and enabled us to collect the Raman spectral information at the single cell level. This shows the potential of using these nanoparticles as multimodal and non-invasive imaging probes for the diagnosis of brain tumors. In addition, the FeCo/C NPs were capable of inducing localized heating in tumors. Furthermore, we demonstrated that the targeted delivery of therapeutic siRNA to bTCs using our FeCo/C NPs, followed by hyperthermia treatment, resulted in the synergistic inhibition of tumor cell proliferation and induced significant cell death, as compared to individual treatments. Hence, a combined therapeutic approach using our multifunctional FeCo/C MNP constructs would facilitate the development of novel therapeutic systems aimed at the successful diagnosis and therapy of malignant cancers by reducing the dose of anti-cancer drugs, mitigating their off-target effects and effectively circumventing drug-resistance in tumors.
10:15 AM - QQ7.5
FeCo-graphitic Carbon Nanocrystals as Multifunctional Imaging and Therapeutic Agents.
Sarah Sherlock 1 , Hongjie Dai 1
1 Chemistry, Stanford University, Stanford, California, United States
Show Abstract Delivery of cancer chemotherapeutics has presented several challenges, including low tumor uptake, inability to monitor distribution in the body and severe side effects for the patient. To address these issues, FeCo-graphitic carbon nanocrystals (FeCo/GC) are currently being developed as a multifunctional imaging and therapeutic agent. These 4 nm nanocrystals contain a superparamagnetic metal core surrounded by a single layer of graphitic carbon produced by chemical vapor deposition. The metal core enables the nanocrystal to function as an MRI contrast agent, capable of either T1 or T2 contrast enhancement. The graphitic surface of the FeCo/GC allows for non-covalent functionalization with phospholipid-polyethylene glycol, imparting biocompatibility and long blood circulation. Due to its size, injection of FeCo/GC leads to high tumor accumulation through the enhanced permeability and retention effect. Tumor uptake can be confirmed via MRI, showing T2 contrast in the tumor following FeCo/GC injection. The enhanced tumor uptake of this material led to investigations into its therapeutic potential. Doxorubicin (DOX) is loaded non-covalently on the graphitic surface, with loadings controllable between 200 and 2000 DOX molecules per nanocrystal. The release of DOX from the nanocrystal is pH sensitive, allowing for a slow, extended drug release once in the acidic tumor environment. The high optical absorption in the near-infrared region makes this material a candidate for combined drug delivery and photothermal therapy. Irradiation of a sample with a near-infrared laser results in selective heating of areas with high accumulation of FeCo/GC. This selective heating and resulting enhanced cell death by combining FeCo/GC-DOX and photothermal heating to ~43° C has been demonstrated both in vitro and in vivo. During in vivo trials, 45 percent of animals treated with the FeCo/GC-DOX + photothermal heating regimen showed complete tumor regression, while there was no regression observed from groups treated with FeCo-GC, DOX or photothermal heating alone. In addition to enhanced therapeutic activity, the side effects of DOX were minimized when delivered on FeCo/GC as compared to DOX injected in its free form. Preliminary in vitro and in vivo toxicity studies indicate the non-toxic and biocompatible nature of these nanocrystals. Overall, these findings provide further motivation for the development of FeCo/GC for use in cancer imaging and therapy.
11:00 AM - **QQ7.6
Highly Stable and Ultrafine Iron Oxide Nanoparticles for Non-invasive Caner Imaging and Targeted Therapy.
Miqin Zhang 1 2 3 , Chen Fang 1 , Omid Veiseh 1 , Forrest Kievit 1 , Zachary Stephen 1 , Hyejune Mok 1 , Hamed Arami 1 , James Park 4 , Donghoon Lee 3 , Richard Ellenbogen 2
1 Materials Science and Engineering, University of Washington, Seattle, Washington, United States, 2 Neurological Surgery, University of Washington, Seattle, Washington, United States, 3 Radiology, University of Washington, Seattle, Washington, United States, 4 Pathology, University of Washington, Seattle, Washington, United States
Show AbstractOne of the major challenges in biomedical applications of nanoparticles is to retain the stability of nanoparticles in application-relevant environments. Nanoparticles are generally electrostatically stabilized by additional surface coating; however, they are prone to aggregation in biological media due to neutralization by ionic species. Additionally, charged nanoparticles tend to adsorb proteins, leading to gradual increase in particle size and eventually to particle precipitation. Here, we present a robust surface engineering approach to produce ultrafine, monodisperse, hydrophilic and functionalized iron oxide nanoparticles that display long-term colloidal stability in biological media, low non-specific uptake by macrophage cells, and long serum half-life. Our results suggest that the presence of the highly dense and stable polyethylene glycol (PEG) coating and the formation of siloxane bonds between PEG chains plays a key role in improving particle stability and biocompatibility. These nanoparticles bear amine and carboxylic groups and are capable of conjugation of a wide variety of biomolecules for intended applications. While iron oxide nanoparticles are one of the most studied nanoparticle systems for biomedical applications, the surface engineering approach introduced here can be applied to any nanoparticles with an oxide surface (either native or oxidized). This presentation focuses on the design and characterization of the highly stable nanoparticles, and their applications in tumor imaging, targeted delivery and therapy.
11:30 AM - QQ7.7
Magnetic Nanoparticles as MRI Constrast Agents and for Selective Targeting of Cells.
Wolfgang Tremel 1 , Thomas Schladt 1 , Kerstin Schneider 1 , Bahar Nakhjavan 1 , Filipe Natalio 1 , Jan Rother 2 , Stefan Weber 3 , Juergen Brieger 3 , Laura Schreiber 3 , Andreas Janshoff 2
1 Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, Mainz Germany, 2 Institut für Physikalische Chemie, Georg August Universität, Göttingen Germany, 3 Universitätsklinikum, Johannes Gutenberg-Universität, Mainz Germany
Show AbstractOne of the goals for biomedical applications of nanoparticles is their functionalization to impart precise biological functions. Nanomaterials can be loaded with low molecular drugs or large molecules like ribonucleic acids (RNA) which are inherently difficult to deliver due to their size and polarity. Nanoparticles are attractive probe candidates because of their (i) size and surface-to-volume ratio, (ii) tunable physical properties directly related to size, composition, and shape, (iii) unusual target binding properties, and (iv) structural robustness. We have developed biocompatible materials by surface functionalization of MnO nanoparticles using polymers or porous silica coatings that simultaneously (i) carry ligands (poly(I:C), CpG, etc.) and (ii) large target molecules (e.g. antibodies for target detection), (iii) small molecules (e.g. drugs) through non-specific binding, and (iv) fluorophors for optical detection. (v) In addition, the nanoparticles can be traced using magnetic resonance imaging (MRI) by virtue of the magnetic properties. Cytotoxicity was evaluated by an electric cell-substrate impedance sensing (ECIS) micromotion assay. The ssDNA and CpG coupled nanoparticles were used to target Toll-like receptors (TLR3 and TLR9) receptors inside the cells and to activate the classical TLR cascade. The multimodal nanoparticles allow optical as well as MRI imaging of cellular trafficking. For in vivo MRI imaging, the water-dispersible functionalized MnO nanoparticles were injected into the tail vene of nude mice. The MnO nanoparticle contrast-enhanced T1-weighted MRI showed contrast-enhanced regions following accumulation of MnO nanoparticles in the tumor.In addition, Janus-type (M-1)@(M-2 oxide) (M-1: Au, Ag, Cu, Pt, Rh, Co and Fe/Pt); M-2 oxide: MnO, Fe3O4) were synthesized by thermal decomposition of metal salts in the presence of metal colloids. In particular, the surface chemistry of both domains can be functionalized independently, where tumor cells were addressed by conjugated antibodies, CpG ligands were attached for immunotherapy and an effective killing of the cells could be achieved under illumination with NIR light. Depending on their chemical anisotropy Janus particles can form superamphiphiles or giant dipoles producing particles with unprecedented properties. The new properties are of considerable interest due to their substantial membrane activity.
11:45 AM - QQ7.8
Multifunctional Nanoparticle Dimers for Combined Cell Targeting, Penetration, and Imaging.
Laura Fabris 1 2 , Bryan Paladini 1 , Paul Mark 1
1 Materials Science and Engineering, Rutgers University, Piscataway, New Jersey, United States, 2 Institute for Advanced Materials Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey, United States
Show AbstractThe rapid growth of the field of nanomedicine has seen the concomitant increase in the demand of multifunctional tools for rapid disease detection, cell targeting and penetration, and highly resolved in vitro and in vivo imaging. Multifunctional nanomaterials represent an ideal class of systems that can address this need. Noble metal nanoparticles (NPs) are especially useful in this context because they can be easily synthesized in different sizes and shapes, can be functionalized with multiple moieties at the same time, and most importantly, can support surface plasmons that can induce extremely high electromagnetic field enhancements [1].Surface enhanced Raman spectroscopy (SERS) relies on the field enhancements induced in the presence of noble metal NPs [2]. This enhancement can be of the order of four orders of magnitude for ensembles of NP monomers and eight orders of magnitude for NP dimers. As a consequence, the SERS signal intensity induced in the presence of NP dimers allows for the detection of analytes with high sensitivity, and due to the fingerprinting capabilities of SERS, also with high selectivity. Metal NP dimers are however also extremely important as imaging tools, that could replace fluorescence based imaging and MRI [3]. In this contribution we will discuss our latest results in the preparation of multifunctional gold and silver NP dimers capable of highly resolved imaging, specific cell targeting, and optimized uptake. The systems presented here will be based on spherical and rod-shaped NPs, and hollow systems will be explored to gain access to multiple plasmon bands. Dithiolated linkers have been used to lock the NPs in a dimer conformation and also act as SERS reporters. The NP surfaces are functionalized with cell targeting moieties, based on the specific recognition capabilities of antigen-antibody and aptamer-protein interactions. Additional capping agents will be cell-penetrating functional groups, including but not limited to cell penetrating peptides. Stability, brightness, and targeting and penetration capabilities of these multifunctional dimers will be examined. Theoretical calculations that have been used to guide and corroborate the experimental results will also be presented.[1] Boisselier, E.; Astruc, D. Chem. Soc. Rev. 2009, 38, 1759.[2] Moskovits, M. J. Raman Spectrosc. 2005, 36, 485.[3] Braun, G.; Lee, S.J.; Laurence, T.; Fera, N.; Fabris, L.; Bazan, G.C.; Moskovits, M.; Reich, N.O. J. Phys. Chem. C 2009, 113, 13622.
12:00 PM - QQ7.9
Selective Release from Gold Nanorods.
Kimberly Hamad-Schifferli 1
1 Biological and Mechanical Engineering, MIT, Cambridge, Massachusetts, United States
Show AbstractNanoparticles are attractive for interfacing to biological systems as nanoscale handles by which to control and manipulate biological processes and reactions. We use laser excitation of gold nanorods to control the release of multiple species independently. Ultrafast laser excitation at the nanorod longitudinal surface plasmon resonance (SPR) heats the nanorod to a high local temperature, inducing melting, which can release biomolecules conjugated to the nanorod. Because the SPR is tunable by changing nanorod aspect ratio, nanorods with different aspect ratios can be excited independently at different wavelengths. We exploit this property for selective and mutually exclusive release of two different payloads of DNA oligos. DNA can be released selectively, and released DNA is still functional. Application of this technology to control blood clotting and combination therapy will be discussed.
12:15 PM - QQ7.10
Rapid Raman Imaging of Stable, Functionalized Nanoshell in Cells.
Yiming Huang 1 , Vimal Swarup 1 , Sandra Bishnoi 1
1 Biological, Chemical & Physical Department, Illinois Institute of Technology, Chicago, Illinois, United States
Show AbstractSurface-enhanced Raman Scattering (SERS) is a sensitive technique for measuring molecules near a metal particle’s surface. More recently, surface enhanced Raman scattering (SERS) based imaging techniques have shown promise for their ability to image a large number of cells in a relatively short amount of time. We investigate the stabilizing capabilities of two different Raman active PEG geometries, a linear pMA-PEG (MW 5000) and a branched pMA-PEG3 (MW 2420). The linear pMA-PEG (5000) stabilizes nanoshells better than a branched Raman-active PEG (pMA-PEG3 (2420)) and commercial PEG (MW 5000). Nanoshells coated with these Raman-active PEG layers are used for semi-quantitative tracking of nanoshells with two different mammalian cell types, human breast cancer (MCF 7) and mouse alveolar macrophage cells (RAW 264.7). With Raman mapping, we can rapidly measure particle uptake within a cell culture in a semiquantitative manner which may prove useful in future nanoparticle toxicity studies. The technique can easily be extended to other metal nanoparticle systems which react readily with thiol groups (gold and silver colloids, gold nanorods, etc.). This new method provides a rapid and convenient technique for imaging mammalian cell cultures containing metal nanoshells stabilized with PEGs.
QQ8: Nanodevices and NanoDrugs for Biomedical Applications
Session Chairs
Robert Sinclair
Thomas Thundat
Wednesday PM, December 01, 2010
Grand Ballroom (Sheraton)
2:45 PM - QQ8.2
Nanowire Nanoelectronics: Building Interfaces with Cells and Tissue at the Natural Scale of Biology.
Tzahi Cohen-Karni 1 , Quan Qing 2 , Didier Casanova 2 , Zhe Yu 2 , SungWoo Nam 1 , Charles Lieber 1 2
1 School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States, 2 Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States
Show AbstractNanostructures and nanostructured substrates show enhanced coupling to artificial membranes, cells, and tissue. Such nano-bio interfaces exist at a length scale natural for biological systems and offer better sensitivity and spatial resolution as compared to conventional planar structures. In this work, we report the electrical properties of silicon nanowires (SiNWs) interfaced with embryonic chicken hearts and cultured cardiomyocytes. We developed a scheme that allows us to manipulate the nanoelectronic to tissue/cell interfaces while monitoring their electrical activity. In addition, we extend our work to the sub-cellular regime, and exceed the spatial and temporal resolution limits of other electrical recording techniques. The flexible assembly of arrays of SiNWs could prove useful for fundamental studies of ion channel biophysics, real-time drug assays and creation of semiconductor / muscle hybrids.
3:00 PM - **QQ8.3
Toward Self-powered Implantable-nanodevices.
Zhong Wang 1
1 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
Show AbstractDeveloping wireless nanodevices and nanosystems is of critical importance for sensing, medical science, environmental/infrastructure monitoring, and even personal electronics. It is highly desirable for wireless devices to be self-powered without using battery. This is a new initiative in today’s energy research for mico/nano-systems in searching for sustainable self-sufficient power sources [1]. It is essential to explore innovative nanotechnologies for converting mechanical energy, vibration energy, and hydraulic energy into electric energy that will be used to power nanodevices. We have invented an innovative approach for converting nano-scale mechanical energy into electric energy by piezoelectric zinc oxide nanowire arrays [2]. The operation mechanism of the nanogenerator relies on the piezoelectric potential created by an external strain; a dynamic straining of the nanowire results in a transient flow of the electrons in the external load due to the driving force of the piezopotential. We have developed the nanogenerator from fundamental science, to engineering integration and to technological scale-up [3-6]. As today, a gentle straining can output 1.2 V from an integrated nanogenerator [6], using which a self-powered nanosensor has been demonstrated [1]. This is a key step for developing a totally nanowire-based nanosystem [6] for in-vitro and in-vivo applications [7,8]. [1] Z.L. Wang “Self-powering nanotech”, Scientific American, 298 (2008) 82-87; Z.L. Wang “Towards self-powered nanosystems: from nanogenerators to nanopiezotronics” (feature article), Advanced Functional Materials, 18 (2008) 3553-3567.[2] Z.L. Wang and J.H. Song “Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays”, Science, 312 (2006) 242-246.[3] X.D. Wang, J.H. Song J. Liu, and Z.L. Wang “Direct current nanogenerator driven by ultrasonic wave”, Science, 316 (2007) 102-105.[4] Y. Qin, X.D. Wang and Z.L. Wang ”Microfiber-Nanowire Hybrid Structure for Energy Scavenging”, Nature, 451 (2008) 809-813.[5] R.S. Yang, Y. Qin, L.M. Dai and Z.L. Wang “Flexible charge-pump for power generation using laterally packaged piezoelectric-wires”, Nature Nanotechnology, 4 (2009) 34-39.[6] S. Xu, Y. Qin, C. Xu, Y.G. Wei, R.S. Yang, Z.L. Wang* “Self-powered Nanowire Devices”, Nature Nanotechnology, 5 (2010) 366.[7] R.S. Yang, Y. Qin, C. Li, G. Zhu, Z. L. Wang “Converting Biomechanical Energy into Electricity by Muscle/Muscle Driven Nanogenerator”, Nano Letters, 9 (2009) 1201 - 1205.[8] Z. Li, G. Zhu, R.S. Yang, A.C. Wang, Z. L. Wang “Muscle Driven In-Vivo Nanogenerator”, Adv. Mater, in press.[9] Thanks to NSF, DOE, DARPA, NIH for support. for details: www.nanoscience.gatech.edu/zlwang
3:30 PM - **QQ8.4
The Workings of NCI Alliance for Nanotechnology in Cancer - From Materials and Device Development to Clinical Opportunities.
Piotr Grodzinski 1
1 , National Cancer Institute, Bethesda, Maryland, United States
Show AbstractNational Cancer Institute is engaged in efforts to harness the power of nanotechnology to radically change the way we diagnose and treat cancer. Research within the Alliance encompasses multiple areas: in vitro diagnostic assays to detect cancer markers with ultrahigh sensitivity and specificity in a multiplexed format; materials, devices and instrumentation for in vivo cancer imaging; targeted, multifunctional nanoparticles with enhanced anti-cancer activity and reduced systemic toxicity; and nanomedicines designed to overcome metastasis and multidrug resistance. The Alliance pursues applied nanotechnologies for cancer detection, therapy, and prevention with an aim to achieve clinical translational stage of these technologies towards culmination of the program. The Alliance funds Centers of Cancer Nanotechnology Excellence, the development of nanotechnology platforms, and intramural Nanotechnology Characterization Laboratory (NCL). NCL provides a spectrum of data on the physical parameters and pharmacological and toxicological characteristics of clinically promising nanomaterials.
4:30 PM - **QQ8.5
Polymeric and Silica Nanoparticles for Cancer Drug Delivery.
Rong Tong 1 , Li Tang 1 , Nathan Gabrielson 1 , Jianjun Cheng 1
1 , University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show AbstractNanoparticles are promising carriers for the delivery of chemotherapeutics for cancer therapy because they are able to carry large payload of therapeutic modality, extravasate leaky tumor vasculature, and mediate sustained drug release in tumor tissues. Of a handful of nanoparticulate carriers being studied, polymeric nanoencapsulates are particularly promising because they can be readily prepared through the co-precipitation of hydrophobic polymers and small molecule drugs in a process called nanoprecipitation. However, nanoencapsulates typically have significant drug burst release, low drug loading, uncontrollable drug encapsulation efficiency and broad particle size distribution. To address these issues, we developed polymeric nanoconjugate with sub-100 nm size, mono-modal size distribution, high drug loading and quantitative drug loading efficiency. Polymeric nanoconjugates also show controlled release profiles without any burst release. We successfully demonstrated nanoconjugate-mediated cancer targeting and in vivo anti-tumor efficacy. To further control particle size, we prepared silica nanoparticles with nearly monodisperse particle sizes in a range of 25 nm to 200 nm. Size-dependent cell uptake and tumor penetration were studied using silica nanoparticles with well controlled size.
5:00 PM - QQ8.6
Dextran Nanogels For In-vivo Drug Delivery.
Alexander Kros 1
1 Dept. Soft Matter chemistry, Leiden Institute of Chemistry, Leiden Netherlands
Show AbstractHydrogel-based drug delivery systems are of interest due to their attractive characteristics, which can lead targeting delivery, extension of circulation time, and reduction of toxicity and side effects. Particularly, hydrogels that can be formed in situ under physiological conditions have recently been paid much attention as promising drug carriers.Hydrogel-based drug carriers have been developed from biocompatible materials, cyclodextrin, dextran and poly(ethylene glycol) and were tested in zebrafish embryos. Maleimide modified dextrans (Dex-mal) was functionalized with cyclodextrins and crosslinked to form a hydrogel using either per-6-thio-beta-cyclodextrin (PSCD) or a combination of mono-thio-beta-cyclodextrin (MSCD) and di-thiolated poly(ethylene glycol) (DSPEG). Using all-trans retinoic acid (RA) as a model hydrophobic drug, a sustained release from these cyclodextrin modified hydrogels was observed in vitro without an initial burst. This is because the cyclodextrin moiety in these hydrogels acts as a binding site for the RA. Furthermore, the nanosized hydrogel particles were injected into early stage zebrafish embryos in order to test in vivo release of RA and biocompatibility. We found the gel particles prepared from Dex-mal, MSCD and DSPEG were suitable for use in zebrafish embryos and it showed the release of RA in the embryos occurs in a controlled manner. In a second example we used the dextran nanogels for the controlled release of proteins.K. Peng, I. Tomatsu, A.V. Korobko, and A. Kros*. Rapid in Situ Forming Cross-linked Dextran/β-cyclodextrin Hydrogels for the Delivery of Hydrophobic Drugs. Soft Matter 2010, 6, 85-87K. Peng, C. Cui, I. Tomatsu, A.H. Meijer, H.P. Spaink, and A. Kros*. Soft Matter, 2010, Accepted.K. Peng, I. Tomatsu and A. Kros*. Light controlled protein release from a supramolecular hydrogel. Chem. Commun. 2010, 46, 4094 - 4096, DOI: 10.1039/c002565h
5:15 PM - QQ8.7
High Thermal Transition Hyperbranched and Dendrimer-like pNIPAAm Synthesis for Targeted Drug Delivery.
Kai Chang 1 , Lindsey Bergman 1 , Lakeshia Taite 1
1 , Georgia Institute of Technology, Atlanta, Georgia, United States
Show AbstractTargeted, controlled drug delivery has long been a goal of the medical and drug development community. Highly branched molecules with large numbers of functional end groups are currently being used for this purpose. We aim to synthesize and modify hyperbranched and dendrimer-like poly(N-isopropylacrylamide) (pNIPAAm), a thermally responsive polymer, for targeted and controlled release purposes. pNIPAAm normally exhibits a sharp thermal transition temperature of 32 °C; modification of this transition temperature to ~45 °C would make the material suitable for in vivo applications. We have synthesized well-defined, physiological transition temperature, hyperbranched pNIPAAm by co-polymerizing with acrylic acid (AAc) using Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. Three different chain transfer agents (CTAs) were used for RAFT polymerization: A linear polymer inducing CTA (CTA1), and two hyperbranched polymer inducing CTAs (CTA2 and CTA3). Characterization of the polymer was conducted using NMR spectrometry, gel permeation chromatography, and UV-Vis Spectrometry. The attached table shows pNIPAAm thermal transition dependence on hyperbranching and copolymerization. Due to the loss of degrees of freedom in hyperbranching, hyperbranched polymers have lower transition temperatures than linear pNIPAAm. This was offset in the copolymers with AAc. The thermal transition temperature widens significantly when pNIPAAm is copolymerized with AAc. We attempted to compensate for the wide transition temperature by using stereocontrol during the polymerization process. This was done by including bulky alcohols during the polymerization of pNIPAAm. Results are promising, with the increased sharpness of transition of both CTA1 and CTA3 syndiotactic polymers. The polydispersity indexes of all polymers ranged from 1.01 to 1.13. Separately, dendrimer-like pNIPAAm synthesis is being pursued on a solid support. Some success has been seen with attachment of pNIPAAm onto resins and branching of linear pNIPAAm chains has been confirmed. Full synthesis of the pNIPAAm dendrimer is in process. Results show that we were able to create well defined linear and hyperbranched pNIPAAm chains with high transition temperatures. Dendrimer-like pNIPAAm synthesis also shows promise with the success of branching. Further characterization studies will be done on the polymers and future experiments will be conducted to test the drug loading capabilities of the constructs.
5:30 PM - QQ8.8
Intracellular Trafficking of Linear-Dendritic Block Copolymer Micelles in DNA Delivery.
Daniel Bonner 1 2 3 , Cheuk Leung 2 , Robert Langer 1 2 3 , Paula Hammond 2 3
1 MIT-Harvard Division of Health Sciences and Technology, MIT, Cambridge, Massachusetts, United States, 2 Department of Chemical Engineering, MIT, Cambridge, Massachusetts, United States, 3 David H. Koch Institute for Integrative Cancer Research at MIT, MIT, Cambridge, Massachusetts, United States
Show AbstractDelivery of nucleic acids has the potential to revolutionize medicine by allowing previously untreatable diseases to be clinically adressed. Replacement of functionally defective or absent protein, induction of apoptosis in distant metastases, and advanced stimulation of the immune system are examples of such therapeutic possibilities. Viral delivery systems have shown immunogenicity and toxicity dangers, but synthetic vectors have lagged in transfection efficiency. Previously, we have developed a modular, linear-dendritic block copolymer architecture with high gene transfection efficiency compared to commercial standards. This rationally designed system makes use of a cationic dendritic block to condense the anionic DNA and form complexes with favorable endosomal escape properties due to the so-called proton sponge effect. The linear chain provides biocompatibility, protection from serum proteins, and can be functionalized with a targeting ligand. Here, we evaluate the functional consequences of chemical structure modifications within the linear-dendritic architecture using confocal microscopy and high throughput techniques to quantitate material performance with respect to intracellular barriers to gene delivery.
QQ9: Poster Session: Nanocellular Interactions, Nanomagnetics, and Nanotherapeutics for Biomedical Applications
Session Chairs
Rashid Bashir
Wenbin Lin
Larry Nagahara
Robert Sinclair
Thomas Thundat
Thursday AM, December 02, 2010
Exhibition Hall D (Hynes)
9:00 PM - QQ9.1
Rare Earth Doped Magnetic Clusters of Gold.
Brahma Yadav 1 , Vijay Kumar 1
1 , Dr. Vijay Kumar Foundation, Gurgaon, Haryana, India
Show AbstractGold clusters have been found to be good for cancer treatment. We have performed ab initio calculations on doping of rare earths in small gold clusters to obtain magnetic clusters using projector augmented wave pseudopotential method within generalized gradient approximation for the exchange-correlation energy. Elemental gold clusters having up to 15 atoms are planar and thereafter 3D structures become favorable. We have explored the changes in the growth behavior when a rare earth atom is doped and studied the variation in the magnetic behavior as a function of size. Our results suggest that gold clusters may have twin advantage of treating cancer as well as be helful in magnetic imaging such as by MRI.
9:00 PM - QQ9.10
Delivery of siRNA and Immobilization of High-Relaxivity MRI Contrast Agents in Mesoporous Silica Microparticles.
Jeremy Steinbacher 1 2 , Sherrill Lathrop 2 , Arti Shukla 2 , Risto Kauppinen 3 , Piper Klemm 4 , Brooke Mossman 2 , Christopher Landry 1
1 Chemistry, University of Vermont, Burlington, Vermont, United States, 2 Pathology, University of Vermont, Burlington, Vermont, United States, 3 Biomedical NMR Facility, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States, 4 Chemistry, University of California, Berkeley, Berkeley, California, United States
Show Abstract We have developed a synthesis of acid-prepared mesoporous silica (APMS) microparticles that exhibit the large surface and pore volume associated with mesoporous solids. Amorphous silica is inherently non-toxic and the pore surfaces and exterior surfaces can be orthogonally functionalized to enhance cell uptake, tumor targeting, and drug loading. We are especially interested in the delivery of short, interfering RNA (siRNA), oligonucleotides that knockdown the proteins associated with specific genes. We have loaded siRNA into our particles, for the first time demonstrating the adsorption of siRNA inside the pores of mesoporous silica. We found that the type and degree of pore modification had drastic effects on the ultimate loading capacity and release efficiency of siRNA, achieving a deliverable dose of approximately 20 micrograms siRNA per milligram of particles. Also, the spatial distribution of the siRNA inside the particles was mapped before and after release using confocal microscopy. We further used APMS as a transfection agent for siRNA in vitro, demonstrating knockdown of GAPDH and ERK2 in malignant mesothelioma cells. Besides delivering siRNA, we used APMS as an MRI contrast agent by attaching a ligand for gadolinium. We immobilized the high-relaxivity TACN-HOPO2-TAM ligand, previously shown to be a very-high relaxivity ligand in solution, via thiol-maleimide click chemistry. Relaxivity measurements of APMS/Gd at 1.5 T showed very large per-particle r1 relaxivities ( > 1e9 mM-1 s-1) because of the large number of gadolinium centers present in each APMS particle. In vivo MRI studies with mice and rats have shown that APMS/Gd are effective contrast agents when administered by intraperitoneal and intravenous injections. Interestingly, microparticles administered by intraperitoneal injection were excreted and intravenous injection resulted in long-circulation in the vasculature, suggesting possible therapeutic uses of these relatively large particles.
9:00 PM - QQ9.12
On the Correlation Between the Properties of Magnetic Fluids and their Specific Absorption Rates.
Yuan Yuan 1 , Diana-Andra Borca-Tasciuc 1
1 Mechanical Engineering, Rensselear Polytechnic Institute, Troy, NY, New York, United States
Show AbstractMagnetic nanofluids can be remotely heated by alternating magnetic field and have significant potential for cancer hyperthermia therapy. Hence, engineering heat generation of magnetic nanoparticle suspensions is necessary for designing fluids with optimized biocompatibility and functionality. In this context, it is essential to investigate factors that influence the heat generation rates, like particle coating, size, and aggregation. In this work, magnetic fluid samples that contain iron oxide nanoparticles with different surfactants and particle dispersion are studied. The susceptibility and magnetization of magnetic fluid samples together with particle and cluster size and specific absorption rate (SAR) are reported. Magnetization was measured by vibrating sample magnetometry, while susceptibility measurement was carried out using a differential impedance method. Particle and cluster size were determined via transmission electron microscopy and dynamic light scattering. The SAR was assessed by measuring the time dependent temperature curves in an external magnetic field. The measured SARs were found to be larger than predictions based on measured properties. These differences could not be readily explained and are subject of further investigations.
9:00 PM - QQ9.13
Core@shell Magnetic Nanomaterials: Fabrication, Characterization, and Biomedical Applications.
Lingyan Wang 1 , Jin Luo 1 , Yao Liu 1 , Chuan-Jian Zhong 1
1 Department of Chemistry , State University of New York at Binghamton, Binghamton, New York, United States
Show AbstractMagnetic nanomaterials represent an important class of advanced materials for biomedical applications in diagnostics, imaging, therapies, etc. This presentation describes gold or silver coated magnetic (M) nanoparticles, so-called core@shell (M@Au or M@Ag) magnetic nanoparticles. Such nanomaterials are interesting because of the unique combination of the nanoscale magnetic core and the functional Au or Ag shell for a wide range of applications. The gold or silver shell imparts the magnetic nanoparticles with many intriguing bio-functional properties. Some of our recent findings in the investigation of the synthesis, characterization and applications of these core@shell magnetic nanoparticles will be highlighted. Examples will focus on strategies for the synthesis of M@Au (M=Fe2O3, Fe3O4, or MnZn Ferrite, etc.) nanoparticles, for potential applications in terms of biological and interfacial reactivities and the antibacterial properties of M@Ag nanoparticles. Implications of the results to understanding both fundamental and practical issues in biomedical applications of core@shell magnetic nanoparticles will also be discussed.
9:00 PM - QQ9.14
Nanoparticles for Cell Labeling: Covalent Attachment of the Drug Protamine to FDA Approved Nanoparticles.
Suelin Chen 2 1 , David Alcantara 1 , Ralph Weissleder 3 , Lee Josephson 1
2 Department of Materials Science and Engineering, MIT, Boston, Massachusetts, United States, 1 Center for Nuclear Medicine and Molecular Imaging, MGH-Harvard Medical School, Charlestown, Massachusetts, United States, 3 Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States
Show AbstractThe desire to track cells by MRI in clinical situations has led to the development of ex-vivo cell labeling methods using complexes of Feridex IV (ferumoxides) with transfection agents. However, the discontinuation of Feridex by the manufacturer calls the utility of these methods into question. To obtain an alternative cell labeling nanoparticle (NP) that would be amenable to clinical translation, we covalently conjugated two approved drugs, protamine sulfate (Pro) and Feraheme (FH), to obtain the cell labeling nanoparticle ProRho-FH. FH is a carboxymethyl dextran-coated iron oxide nanoparticle approved for treating iron anemia, and protamine is an arginine rich peptide with membrane translocating properties used in the clinic to reverse the anti-coagulant effects of heparin. First, the carboxyl groups on FH were converted to amine groups, yielding amino-FH. Second, a fluorescent protamine was obtained by reacting its only amine, the N-terminus, with rhodamine (Rho) to yield ProRho. We then conjugated the C-terminus of ProRho to amino-FH. Since iron oxide nanoparticles and protamine may associate through electrostatic interactions, we demonstrated that ProRho was associated with FH through a covalent bond. U87 glioma cells and mouse mesenchymal stem cells (MMSCs) internalized between 2 and 10 pg Fe/cell of ProRho-FH and those labeled cells were readily detected by fluorescence, iron staining, MRI in vitro, and MRI after implantation in a mouse brain. ProRho-FH is a fluorescent, superparamagnetic NP that has been designed with many features facilitating its clinical translation and has potential as a reagent for loading and tracking cells by MRI for cell-based therapies in the clinic.
9:00 PM - QQ9.15
Size-tunable Properties of Magnetic Nanostructures (MNS) for Biomedical Applications.
Mrinmoy De 1 , Hrushikesh Joshi 1 , Vinayak Dravid 1
1 , Northwestern University, Evanston, Illinois, United States
Show AbstractMagnetic nanostructures (MNS) in their superparamagnetic form (~ < 10-15 nm nominal size) are promising materials systems for contrast enhancement in magnetic resonance imaging (MRI) and thermal-activation therapeutics via RF heating. These biomedical applications and associated properties are very much dependent on the structure, composition and size/shape of MNS. Although there are many speculations on the effect of various parameters on MNS, the size dependent properties are not well understood, largely due to challenges in size-selective large-scale synthesis for precise measurements. Herein we report the effect on size of iron oxide MNS on hydrodynamic radius, zeta potential, magnetic property and relaxivity. For this study, we have synthesized a wide range of monodispersed iron oxide MNS, from 7nm to 20nm nominal size and phase transferred to aqueous media in excellent colloidal suspension without any aggregation. The dynamic light scattering (DLS) study and zeta potential measurement were carried out to determine the hydrodynamic radius and surface charge. The hydrodynamic radius follow the linear correlation but the zeta potential does not maintain it due to nonlinear mass/charge ratio relations with varying size. We have also conducted correlative studies of magnetic saturation (Ms) and T2 relaxivities. The presentation will highlight the size dependent correlation and tailoring of MNS properties for desired biomedical applications.
9:00 PM - QQ9.16
Investigation of Nanofibrillar Influence on Cell-Cell Interactions of Astrocytes by Atomic Force Microscopies.
V. Mujdat Tiryaki 1 , Virginia Ayres 1 , Adeel Khan 2 , Dexter Flowers 3 , Ijaz Ahmed 4 , Roberto Delgado-Rivera 4 , Sally Meiners 4
1 , Michigan State University, East Lansing, Michigan, United States, 2 , Western Michigan University, Kalamazoo, Michigan, United States, 3 , Wayne State University, Detroit, Michigan, United States, 4 , University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, United States
Show AbstractA comprehensive atomic force and scanning probe recognition microscopy study of important differences in cell-cell interactions of astrocytes in a nanofibrillar environment that recapitulates the extracellular matrix (ECM) is presented. Astrocytes are key cellular components of the central nervous system (CNS) that function as cellular intermediaries between capillaries and neurons. They interact with the nutrient-bearing capillaries across an ultra-dense nanofibrillar ECM called a basement membrane, which surrounds each capillary and contributes to the blood-brain barrier. In previously reported work [1], we demonstrated that astrocytes cultured on synthetic polyamide nanofibrillar surfaces that mimic the architecture of the capillary basement membrane assumed morphological forms that recapitulated their physiology within the developing central nervous system. In the present work, atomic force microscopy in survey and recognition microscopy modes is used to investigate nanoscale responses to nanofibrillar versus planar culture surfaces. Three significant differences in cell-cell interactions are identified and reported: 1) extensions, 2) junction types, and 3) cellular morphologies. The importance of investigating cellular responses in an environment that recapitulates the nanoscale physical, architectural and chemical properties of a native extracellular matrix is discussed.[1] Delgado-Rivera, R, Harris, SL, Ahmed, I, Babu, AN, Patel, R, Kamal, J, Ayres, V, Flowers, D, Meiners, S, 2009. Increased FGF-2 secretion and ability to support neurite outgrowth by astrocytes cultured on polyamide nanofibrillar matrices. Matrix Bio. 28: 137-147.
9:00 PM - QQ9.17
Morphological Evaluation of Osteoblast (MC3T3) Cell Interaction on TiO2 Nanotubes Using FIB Milling and SEM investigation Techniques.
Tolou Shokuhfar 1 , Owen Mills 2 , Jen-Yung Chang Gami 1 , Chang Kyoung Choi 1 , Craig Friedrich 1
1 Mechanical Engineering, Michigan Technological University, Houghton, Michigan, United States, 2 Materials Science and Engineering, Michigan Technological University, Houghton, Michigan, United States
Show AbstractIn this study a self-assembled arrays of titanium dioxide nanotube was used to investigate the adhesion, spreading and substrate interaction of osteoblast cells. Focused ion beam (FIB), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and optical microscopy observation of osteoblast were used to investigate the cell proliferation, morphology and adhesion at the nanotube interfaces. Chemical analysis from the osteoblasts, osteoblast-nanotube interface, and milled areas of cell attached to nanotubes, revealed that the lipid bilayer of the cells has been grown inside the nanotubes, resulting in complete coverage and clogging of the nanotubes. The results indicated that osteoblasts spreading, adhesion and substrate interaction is higher in surfaces covered by nanotubes compared to bare surfaces of commonly used surgical pure Ti and Ti6Al4V alloys.
9:00 PM - QQ9.18
In Vitro Primary Hepatocyte Culture on Solid State Synthesized Multiwall Nanotube Scaffolds for Liver Tissue Engineering.
C. Lewis Azad 1 2 , C. Azura Che Abdullah 2 , Marcio Dias Lima 1 , Raquel Ovalle Robles 1 , Xavier Lepro Chavez 1 , Shaoli Fang 1 , Ray Baughman 1 , Richard Sear 2 , Alan Dalton 2 , Nick Plant 3
1 Department of Chemistry, Alan G. MacDiarmid NanoTech Institute UT Dallas/University of Surrey, Richardson, Texas, United States, 2 Faculty of Engineering and Physical Sciences, University of Surrey, Guildford United Kingdom, 3 Department of Biochemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford United Kingdom
Show AbstractHepatocytes constitute roughly 70% of the liver: These cells are frequently utilized in liver tissue engineering as well as for studies of pharmacological and toxicological effects of drugs. It is well known when working with primary hepatocyte cells in monolayer culture that they rapidly de-differentiate, resulting in short-term survival and reduced metabolic capacity. As these cells perform vital roles in drug metabolism and in maintaining body homeostasis, there is an imperative need for constructing substrates that promote their survival and retain the liver specific function in culture. Our current study is focused on developing 2-Dimensional and 3-Dimensional biocompatible multiwall nanotube (MWNT) scaffolds that regulate the cell environment along with cell-cell interactions to successfully maintain the polarity and liver specific function in hepatocytes in vitro. Here we present results for the cell adhesion, spreading, morphology, as well as polarity assays of primary rat hepatocytes on anisotropic substrates with nanoscale features based on solid state fabricated MWNT sheets and yarns. Following incubation, cells on monolayer and sandwich configuration were monitored and evaluated by means of optical microscopy, Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). Preliminary results show that hepatocytes adhered to and proliferated while self-aligning along the longitudinal nanoscale grooves formed by the MWNTs. To conclude, we have successfully engineered and identified scaffolding materials whose nanoscale topography directly guides primary hepatocyte cell adhesion and liver tissue growth. In addition, the scaffolds are able to sustain the liver-specific function of these hepatocyte cells and we continue to explore their potential uses in the study of liver pharmacokinetics.
9:00 PM - QQ9.19
Heterogeneous Morphology Modulation of Senescent Human Mesenchymal Stem Cells on Chemically-modified Surfaces.
Sung Hoon Kim 1 , Byung Man Lee 1 , Seul Ki Min 1 , Hwa Sung Shin 1
1 Biological Engineering, Inha University, Incheon Korea (the Republic of)
Show AbstractHuman mesenchymal stem cell (hMSC) is a multipotent and recognized as a source for tissue engineering or cell therapy. It is, therefore, imperative to acquire enough hMSCs, maintaining self-renewal and differentiation potential. However, aged hMSCs are prone to have a gradual decline in differentiation and proliferation potential with continual division cycle during in vitro culture. hMSCs’ physiocochemical properties are highly implicated with their micro-environment called ‘stem cell niche’. This research is for investigating hMSC morphologies and their heterogeneities on chemically defined self-assembly monolayer surfaces. Surface energy regulated aged hMSC morphology and its heterogeneity. Initially self-clumped cells on low surface energy surface showed higher homogeneity than those on high surface energy surfaces. These results can support invaluable considerations in designing scaffolds for tissue engineering or in modulation of implantation environment.
9:00 PM - QQ9.2
Iron Fortification: Flame-made Nanostructured Mg- or Ca-doped Fe Oxides.
Jesper Knijnenburg 1 , Florentine Hilty 2 , Alexandra Teleki 1 , Frank Krumeich 1 , Richard Hurrell 2 , Michael Zimmermann 2 , Sotiris Pratsinis 1
1 Department of Mechanical and Process Engineering, ETH Zurich, Zurich Switzerland, 2 Institute of Food Nutrition and Health, ETH Zurich, Zurich Switzerland
Show AbstractIron deficiency affects approximately 2 billion people worldwide, especially young women and children. Food fortification with iron is a sustainable approach to alleviate iron deficiency but remains a challenge. Water-soluble compounds with high bioavailability (e.g. the “gold standard” FeSO4) usually cause unacceptable sensory changes in foods, while compounds that are less reactive in food matrices are often less bioavailable [1]. Solubility (and therefore bioavailability) can be improved by increasing the specific surface area (SSA) of the compound, i.e. decreasing its particle size to the nm range. Rohner et al. [2] prepared nanostructured FePO4 by flame spray pyrolysis (FSP) with SSA as high as 195 m2/g (~11 nm) that exhibited high solubility and bioavailability comparable to FeSO4 (the “gold standard” as supplement to alleviate iron deficiency) in Sprague-Dawley rats but with improved sensory properties. Recently Hilty et al. [3] developed zinc-containing nanostructured iron compounds with nutritionally attractive Zn-compounds by FSP. The addition of Zn increased iron solubility and (as shown recently) bioavailability that was comparable to FeSO4 but with improved sensory (color) properties [4]. Bioavailability was determined in-vivo by actual administration of these fortificants to rats, where no adverse effects in organs and tissues were found. Additional doping of Zn/Fe oxide with Mg increased Fe absorption and improved powder color [4]. Here, iron oxide-based nanostructured compounds with Mg or Ca are made using FSP [5]. Addition of either element increased iron solubility to a level comparable to iron phosphate. Furthermore, these additions lightened the powder color and sensory changes in fruit yoghurt were less prominent than for FeSO4. [1]Hurrell RF. Fortification: Overcoming technical and practical barriers, Journal of Nutrition (2002), 132, 806S-812S.[2]Rohner F, Ernst FO, Arnold M, Hilbe M, Biebinger R, Ehrensperger F, Pratsinis SE, Langhans W, Hurrell RF & Zimmermann MB. Synthesis, characterization, and bioavailability in rats of ferric phosphate nanoparticles, Journal of Nutrition (2007), 137, 614-619.[3] Hilty FM, Teleki A, Krumeich F, Buchel R, Hurrell RF, Pratsinis SE & Zimmermann MB. Development and optimization of iron- and zinc-containing nanostructured powders for nutritional applications, Nanotechnology (2009), 20, 475101.[4]Hilty FM, Arnold M, Hilbe M, Teleki A, Knijnenburg JTN, Ehrensperger F, Hurrell RF, Pratsinis SE, Langhans W & Zimmermann MB. Iron from nanocompounds containing iron and zinc is highly bioavailable in rats without tissue accumulation, Nature Nanotechnology (2010), 5, 374-380.[5] Hilty FM, Knijnenburg JTN, Teleki A, Krumeich F, Hurrell RF, Pratsinis SE & Zimmermann MB. Addition of Mg and Ca to nanostructured Fe2O3 improves solubility in dilute acid and sensory characteristics in food, Journal of Food Science (2010), submitted.
9:00 PM - QQ9.20
Compartmental Culture of Embryonic Stem Cell-derived Neurons in Microfluidic Devices for use in Axonal Biology.
Sung Hoon Kim 1 , Byung Man Lee 1 , Seul Ki Min 1 , Hwa Sung Shin 1
1 Biological Engineering, Inha University, Incheon Korea (the Republic of)
Show AbstractAxonal pathology has been clearly implicated in neurodegenerative diseases making the compartmental culture of neurons a useful research tool. Primary neurons have already been cultured in compartmental microfluidic devices but their derivation from an animal is a time-consuming and difficult work and has a limit in their sources. Embryonic stem cell (ESC)-derived neurons (ESC_Ns) overcome this limit, since ESCs can be renewed without limit and can be differentiated into ESC_Ns by robust and reproducible protocols. In this research, ESC_Ns were derived from mouse ESCs in compartmental microfluidic devices, and their axons were isolated from the somal cell bodies. Once embryoid bodies (EBs) were localized in the microfluidic culture chamber, ESC_Ns spread out from the EBs and occupied the cell culture chamber. Their axons traversed the microchannels and finally were isolated from the somata, providing an arrangement comparable to dissociated primary neurons. This ESC_N compartmental microfluidic culture system not only offers a substitute for the primary neuron counterpart system but also makes it possible to make comparisons between the two systems.
9:00 PM - QQ9.21
Investigation of Focal Adhesions by Nanocontact Printing Using Size Tunable Polymeric Nanopillars.
Chiung Wen Kuo 1 , Peilin Chen 1
1 Research Center for Applied Sciences, Academia Sinica, Taipei Taiwan
Show AbstractHere we describe a simple approach to create various sizes of protein nanoarrays for the investigation of cell adhesion. Using a combination of nanosphere lithography, oxygen plasma treatment, deep etching and nanomolding process, well-ordered polymeric nanopillar arrays have been fabricated with diameter in the range of 50 – 250 nm. These nanopillar arrays have been used as stamps for nanocontact printing to create fibronectin nanoarrays, which were used to study the size dependent formation of focal adhesion. When CHO cells were cultured on the fibronectin nanoarrays, it was found that cells can adhere and spread on all the fibronectin nanoarrays tested in this experiment and the protruding edges of the cells followed the fibronectin nanopatterns even with pattern size as small as 50 nm. The average size of focal adhesion was observed to decrease as the diameter of fibronectin nanopatterns decreased. The size tunable nanosphere lithography offers several advantages in preparing well-ordered protein nanoarrays for many potential applications in cell biology and biosensors including 1) fast fabrication where stamps could be prepared within hours and protein arrays could be printed within seconds. 2) Diameter and separation distance of protein nanoarrays could be tuned independently. And 3) this technique is a high throughput and high resolution printing process where large-area protein nanoarrays with pattern size as small as 50 nm could be produced within seconds.
9:00 PM - QQ9.22
Fabrication and Characterization of Hydrogel Nanofibers for Mimicking Stem Cell Microenvironments.
Andrea Mannarino 1 , Yunyi Yao 2 , Michael Zonca 1 , Nurazhani Abdul Raof 1 , Jun Gu 2 , Yubing Xie 1
1 College of Nanoscale Science and Engineering, University at Albany, Albany, New York, United States, 2 New York State Department of Health, Wadsworth Center, Albany, New York, United States
Show AbstractStem cells are promising sources for cell therapy, diagnostics and drug discovery. The therapeutic potential is dependent on the ability to direct stem cell proliferation and differentiation, which is governed primarily by its microenvironment at nanoscale size. It is therefore important to fabricate nanobiomaterials to mimic the microenvironment for stem cells, which includes the extracellular matrix (ECM), soluble factors, and neighboring cells. In particular, the nanofibrous ECM provides the physical and chemical interactions that can help determine the fate of stem cells. ECM is composed of polysaccharide gels and fibrous proteins. Electrospun nanofibers have been proven to be effective for promoting stem cell growth in culture. By hypothesizing that incorporating hydrogel into the nanofiber system will better mimic the physical properties of the stem cell microenvironments, we fabricated alginate nanofibers using electrospinning of alginate/PEO aqueous solution. These alginate hydrogel nanofibers were characterized by scanning electronic microscopy (SEM, LEO1550), atomic force microscopy (AFM, Veeco Bioscope CATALYST), neural stem cell toxicity assay, and embryonic stem cell (ESC) growth assay. The nanofibrous structure image of alginate hydrogel was shown by SEM and further confirmed by AFM. However, the neurotoxicity assay demonstrated that alginate hydrogel nanofibers prevented the growth and neurosphere formation during the primary culture of mouse neural stem cells isolated from the subventricular zone. The hydrogel nanofibers were further modified with polylysine, gelatin and alginate by self-assembly. The elasticity of alginate nanofibers could be changed by these surface modifications as well. The chemical modification with polylysine and gelatin retained the morphology of nanofibers and facilitated the formation of the neurospheres in various sizes. The hydrogel nanofibers were further characterized by examining the expression of pluripotency markers and differentiation potential of ESCs grown on these hydrogel nanofibers. It was demonstrated that chemically modified hydrogel nanofibers maintained stem cell pluripotency. In summary, we have demonstrated a hydrogel nanofibrous system with a variety of surface chemistry characteristics and tunable elasticity, which shows a great potential for directing stem cell growth/differentiation.
9:00 PM - QQ9.23
Sensing of Extracellular Matrix Topographical Cues During Neurite Outgrowth.
Kyung-Jin Jang 1 2 , Min Sung Kim 2 , Olivier Pertz 3 , Kahp-Yang Suh 2 1
1 Interdisciplinary Program in Nano-Science and Technology, Seoul National University, Seoul Korea (the Republic of), 2 School of Mechanical and Aerospace Engineering, Seoul National University, Seoul Korea (the Republic of), 3 Institute for Biochemistry and Genetics, Dept. Biomedicine, University of Basel, Basel Switzerland
Show AbstractThe process of neurite outgrowth is the initial step in producing the neuronal processes that wire the adult brain. Most of the current cell biological concepts on how this complex morphogenetic event occurs have been derived from classic two-dimensional (2D) cell culture systems, but it is unknown how topographical cues in the extracellular matrix (ECM) might influence this behavior. Using a novel nanopatterning technique, we show that, when the ECM protein laminin is presented on ridge patterns with submicrometer size features, it evokes different neurite outgrowth responses than on classic 2D environments. The patterned substrate not only allows neurite orientation along the ridges but also leads to a robust increase in neurite length compared to the 2D environment. This is accompanied by prominent changes in morphology. Thus, on the patterned substrate, a lower amount of shorter filopodia are observed on the neurite shaft and soma compared with the 2D environment. Furthermore, two distinct filopodia populations are observed on the growth cone, one consisting of prominent, F-actin rich filopodia that align with the top of the ridges, a second one which consists of thin filopods that are not aligned on the ridges. We show that increased neurite length does not occur because of more rapid neurite tip growth, but mostly is the result of a lack of neurite retraction events that are typical of the 2D environment. Using time-lapse microscopy, we show that the guidance mechanism on the pattern is dependent on filopodium orientation at the growth cone. We find that F-actin rich filopodia oriented on the top of the ridges are very stable, whereas “exploratory” filopodia that are not oriented are highly unstable and ultimately disappear. This mechanism allows to bias the neurite outgrowth in the direction of the line pattern.
9:00 PM - QQ9.24
Investigation of a-C:H Film Coating Effect on Cell Mobility.
Yasuharu Ohgoe 1 , Kazuhiro Nonaka 1 , Kenji Hirakuri 2 , Akio Funakubo 1 , Yasuhiro Fukui 1
1 , Tokyo Denki University, Saitama Japan, 2 , Tokyo Denki University, Tokyo Japan
Show AbstractAmorphous hydrogenated carbon including diamond-like carbon (DLC) film has attractive properties of biocompatibility. Radio frequency (r.f.) plasma chemical vapor deposition (CVD) method is possible to deposit a-C:H film at low temperature such as polymeric materials. In recent studies, a-C:H film coating has been expected as surface modification technology for biomaterials. In our previous works, we have developed a-C:H film deposition technique for tissue engineering and deposited on micro Segmented polyurethane (SPU) fibers as scaffold. The a-C:H film has been successfully deposited on each fiber of the scaffold sheet by r.f. plasma CVD. The purpose of such coating is investigation of effect of a-C:H film deposition for cell growth. And then, it was observed that the a-C:H film coatings enhanced cell growth and cell adhesion. This means a-C:H film technique is useful for tissues engineering in development of medical appliances such as a synthetic vascular graft.In this study, we focus on a-C:H film coatings for engineering functional tissues based on the previous works. a-C:H film has been deposited on SPU scaffold sheet. We investigated on structural and compositional effects of the a-C:H film on cell growth and mobility as an investigation of biological response at each fiber. The surface composition, roughness, potential, structures, and wettability of the a-C:H was estimated using X-ray photoelectron spectrometer (XPS), Atomic force microscopy (AFM), and surface energy measurement. And then, mouse fibroblasts (NIH 3T3) cells were grown on the a-C:H film deposited scaffold. The cell behaviour was monitored by video camera and the cell mobility was analysed. The deposition condition of the a-C:H film on the scaffold fiber sheet is possible to control cells mobility by a-C:H film surface conditions. It was observed that a-C:H film coatings have an effect of mouse fibroblasts cell mobility for biocompatibility in the scaffold sheet. These results suggest that a-C:H coating is a promising approach for tissue engineering.
9:00 PM - QQ9.25
Electrospun Three-dimensional Microtents for in vitro Study of Endothelial Cells.
Bongsu Kim 1 , Yi Zhao 1
1 Biomedical Engineering, Ohio State University, Columbus, Ohio, United States
Show AbstractThis paper reports a novel fabrication approach for creating 3D microstructures made up of polymer nanofibers. By combining the strengths of microfabrication and electrospinning, 3D microtents with high precision are fabricated with minimal cost and fabrication complexity. Such structures can host and manipulate live cells to have morphological similarity with natural tissues. In particular, these structures can mimic curved surfaces in many natural tissues, e.g. vessel wall, and allow the study of cellular response to mechanical loads in such tissues.An array of SU-8 micropillars is fabricated by standard photolithography. The diameter, height of the micropillars and the spacing between the micropillars are systematically changed. A layer of 10 nm thick Ti is deposited on the sample by sputtering to make the sample surface conductive. Electrospinning of poly(etherurethane)urea (PEUU) polymer is then performed under the voltage bias of 12 kVDC using the conductive sample as the collecting surface. The distance between the spinning tip and the collecting surface is set at about 15 cm. As the nanofibers being whipped on the micropillars, 3D fibrous structures with sloped sidewalls are developed, forming a “tent” shape. The result shows that when the micropillars are very close to each other, most nanofibers do not exhibit obvious sagging down. Instead, they bridge over the pillar’s tops and form a 2D sheet. As the spacing between the micropillars increases, the nanofibers sag down and anchor on the ground substrate between the micropillars, forming microtents.The morphology of the microtents is examined before and after they have been peeled from the collecting surface. It is observed that the height of the microtents reduce up to 50% upon peeling. This is believed due to the elastic properties of PEUU and the high tension in the nanofibers. Another outcome of the peeling is that the averaged pore sizes of fibers on the top surface of the micropillars and on the ground substrate both decrease. The result also shows that the half cone angle at the peak of each microtent does not depend on the top diameter of the micropillars. The averaged half cone angle slightly increases as the micropillar height decreases. Moreover, the angle seems to decrease when the spinning is performed at small flow rates. Overall, the curvature of the microtents can be controlled by selecting electrospinning parameters and changing geometries of SU-8 micropillars.Human trabecular meshwork endothelial cells are successfully cultured on the concave surface of the microtents. Scanning electron microscopy shows that the endothelial cells can form an engineered endothelium with morphological similarity with the natural endothelium. Such structure with controllable curvature allows study of endothelial cells under in vivo like conditions, especially for studying cellular response to complex pattern of compressive and tensile stresses.
9:00 PM - QQ9.26
Designer Hydroxyapatite Surfaces with Tunable Nanoscale Morphology for Controlling Integrin-Mediated Cell Adhesion.
Parimal Bapat 1 , Renato Camata 1
1 Physics, University of Alabama at Birmingham, Birmingham, Alabama, United States
Show AbstractCell adhesion is mediated by the integrin family of transmembrane glycoproteins. Over two dozen different integrins are known to be expressed in humans and contribute to the specific binding of cells to proteins of the extracellular matrix (ECM). Understanding how the ECM microenvironment affects integrin function is a major goal of regenerative medicine and tissue engineering. Recent studies of cell behavior show that integrin function is affected by the topographical features, dissolution behavior and distribution of RGD peptides on a surface. We have designed hydroxyapatite surfaces that may help elucidate the mechanisms through which chemical and nanotopographical features cooperate in determining cell behavior. The surfaces comprise hydroxyapatite (HA) nanocrystals of well defined size and inter-particle spacing on PEG films. Tunable nanocrystal diameter enables modulation of substrate nanotopography whereas variable inter-particle spacing permit specified density of anchoring points for biomolecule functionalization. In our designer synthesis, an HA target is ablated in a tube furnace reactor at 800-900°C in 720 Torr of flowing Ar/H2O using a KrF excimer laser. The nanoparticle aerosol formed by laser ablation passes through an ionization zone and the charged particles are sorted according to size using a differential mobility analyzer. Size-selected nanoparticles are deposited by gas-phase electrophoresis on the PEG films leading to a surface of bioactive HA nanoislands on an otherwise nonfouling surface. Atomic force microscopy shows that this method can create uniformly dispersed nanoparticle deposits with size tunable in the 10–100 nm range and size dispersion of ~15%. X-ray diffraction (XRD) on calibration surfaces indicate that the HA nanocrystals can be tailored to the desired level of crystallinity, as well as to other calcium phosphate phases such as tricalcium phosphate and amorphous HA. For example, XRD on samples obtained at 950°C show that the nanoparticle phase changes from HA to tricalcium phosphate as the laser fluence varies from 1.7 to 5.4 J/cm2. Post-deposition annealing of HA-nanocrystal surfaces at 800°C enables further control of particle crystallinity. These surfaces can be further functionalized by the adsorption of peptides to the HA nanoislands. This is particularly the case for RGD peptides conjugated to polyacidic aminoacid domains, which have high affinity for HA surfaces. Because of their spatial specificity, these designer surfaces may allow direct observation of controlled peptide adsorption as well as enable multivariate studies to decouple the effect of nanotopography and biochemical motifs on cell adhesion and motility, with relevance for applications in bone tissue engineering and regeneration. Characterization studies on these designer surfaces using grazing incidence X-ray diffraction (GIXRD) (wide angle) performed on the LNLS synchrotron light source will also be discussed.
9:00 PM - QQ9.27
A Novel Injectable Colloidal Nanogel for Two-Stage Drug Delivery.
Meng-Hsuan Hsiao 1
1 , National Chiao Tung University, Hsinchu Taiwan
Show AbstractA newly-developed amphiphilic carboxymethyl-hexaonyl chitosan (CHC) developed in this lab was employed to formulate into an injectable hydrogel for drug delivery, by neutralizing the positively-charged CHC with negatively-charged salt (β-glycerophosphate). Unlike conventional hydrogel with 3-D network, this CHC gel exhibits an assembly of colloidal nanocapsules, forming a highly-porous nanostructure (termed as nanogel). A thermo-responsive sol-to-gel transition of CHC nanogel was observed at physiological conditions, which facilitates invasive medication purpose, such as injectable drug delivery system. The CHC nanogel is constituted by aqueous solution (more than 97%), gelation occurred even with less than 1% CHC nanocapsules, making the nanogel highly biocompatible (A10 asay). The Amphiphilic nature of the nanogel permitted a subsequent application to carry drugs of various water affinity (from water soluble, ethosuximide (ESM), to water insoluble, camptothecin (CPT)), and the controlled drug release behavior in vitro has been systematically investigated. The experimental results indicated that the CHC nanogel exhibited a long-term, sustained release profile for both types of drugs and release kinetics suggested a two-stage profile, suggesting a bimodal release pattern, and has been confirmed to be a result of drug distribution, i.e, within the nanocapsules and inter-capsule regions. Besides, CHC nanogel is hybridized with magnetic nanoparticle to form a magnetically-controllable drug delivery system which is able to trigger by an external magnetic field, making the multifunctionalized nanogel a potential injectable drug delivery nanodevice.
9:00 PM - QQ9.28
Platforms for Controlled Release Based on Blend Polymer Films Containing Strong and Weak Polyelectrolytes.
Yeongseon Jang 1 , Bulent Akgun 2 , Sushil Satija 2 , Kookheon Char 1
1 School of Chemical and Biological Engineering, Seoul National University, Seoul Korea (the Republic of), 2 , National Institute of Standards and Technology Center for Neutron Research, Gaithersburg , Maryland, United States
Show AbstractPlatforms for the controlled release based on model blend polymeric multilayer films consisting of a cationic polyelectrolyte (linear poly(ethylene imine), LPEI) and a mixture of two different types of anionic polyelectrolytes, sodium poly(styrene sulfonate) (SPS; strong polyelectrolyte (PE)) and poly(methacrylic acid) (PMAA; weak PE), have been designed and their release behavior was studied in the present study.The blend polymeric multilayer films with well-defined internal structure were prepared by the spin-assisted layer-by-layer (LbL) deposition and the release behavior of target weak PE chains (i.e., PMAA in the present case) from the model platforms has been systematically investigated with neutron reflectivity (NR) combined with ellipsometry, AFM, QCM, and FT-IR spectroscopy.The rapid burst of the multilayer films consisting solely of weak PE pairs is dramatically suppressed by adding a small amount of the strong PE in the blend layers, which is believed to provide a robust skeleton in the blend layers irrespective of pH. In addition, the release kinetics of the weak PE (PMAA) could be accurately controlled by simply varying the content of SPS in the blend layers. This blend approach and its results demonstrated in the present study would give insights on the controlled release of target active materials from the polymeric multilayer thin films, leading to the development of versatile drug delivery platforms in response to external stimuli for many biomedical applications.
9:00 PM - QQ9.29
Anti-tumor Chloroquine-gold Nanocomposites and Their Binding Interaction with Bovine Serum Albumin- Biophysical and Biochemical Aspects of Protein Binding.
Prachi Joshi 1 5 , Soumyananda Chakraborti 2 , Pinak Chakrabarti 2 , Surinder P. Singh 3 , Vinay Gupta 4 , Z. Ansari 5 , Virendra Shanker 1
1 LMD, NPL, New Delhi India, 5 , JMI, Delhi India, 2 , Bose Institute, Kolkata India, 3 , UPRM, Mayaguez United States, 4 , Delhi University, Delhi India
Show AbstractWe have conjugated an important drug molecule, chloroquine onto small-sized, thiol-stabilized gold nanoparticles. In addition to malaria treatment, chloroquine is also effective as an antiviral (against influenza, HIV-1) and antitumor drug. The gold nanoparticles were prepared by using sodium borohydride as reducing agent and 11-mercaptoundecanoic acid as thiol capping agent in aqueous medium. The formation of gold nanoparticles was confirmed by using optical spectra for characteristic surface plasmon band; the average size of gold nanoparticles was found to be ~ 7 nm from electron microscopy measurements. The chloroquine conjugation was carried out by using EDC/NHS chemistry and the binding was studied by using Fourier Transform Infrared spectroscopy. The amide bond linking the drug to nanoparticle gets cleaved at acidic pH conditions and the approximate amount of released chloroquine was measured by optical density measurement. The chloroquine-conjugated gold nanocomposites were found to interact efficiently with bovine serum albumin protein. The binding was studied by using isothermal titration calorimetry and fluorescence spectroscopy. The thermodynamic parameters suggest that the binding is driven by contributions from both enthalpy and entropy. The binding occurs without changing the protein’s secondary structure but with minor alteration in tertiary structure. The chloroquine-conjugated gold nanocomposites were observed to bind at site I of subdomain IIA in protein bovine serum albumin, as revealed by warfarin displacement measurements, and this was also supported by the fluorescence quenching experiments involving Trp212. Unraveling the nature of interactions of chloroquine-conjugated gold nanocomposites with bovine serum albumin and the observation on the pH-sensitive release of the drug would pave the way for the design of improved drugs, enriching the field of nanomedicine and nano-biotechnology. The anti-tumor effects of the prepared nanocomposite, vis-à-vis chloroquine itself, have been demonstrated using MCF-7 breast cancer cell line.
9:00 PM - QQ9.3
Fe3O4-capped Mesoporous Silica Nanoparticles for Magnetically Remote-controlled Drug Release and MR Imaging.
Po-Jung Chen 1
1 Materials Sciences and Engineering, National Chiao Tung University, Hsinchu Taiwan
Show Abstract Nanoparticluate Fe3O4 has been most studied and employed not only as a contrast agent but also as a drug carrier. A novel nanocarrier (MSN@Fe3O4) is using monodispersed Fe3O4 nanoparticles to cap mesoporous silica nanoparticles (MSN) through a chemical bonding. The chemical links permit the magnetic nanoparticles (Fe3O4) as nano-caps to completely cover the mesoporous pores on the surface of mesoporous silica matrix. Without magnetic stimulus, no or a negligible amount of the drug can allow released from the MSN@Fe3O4. However, while apply an external controllable magnetic field, an amount of Fe3O4-caps can remotely removed and gives tunable release profiles for an anticancer drug, (S)-(+)-Camptothecin (CPT), with various dosages depending upon the strength and time period of magnetic induction. The transverse relaxivities (r2) of the MSN@Fe3O4 nanocarriers was measured to be about 121.57 s-1mM-1Fe, which reveals an excellent magnetic resonance image. Therefore, the MSN@Fe3O4 nanocarriers could be as a T2- type MR contrast enhancement agent for cell or molecular imaging. In addition, the MSN@Fe3O4 nanocarriers also demonstrate fairly high cell uptake efficiency from the A549 cell line and when the magnetic field trigger that would induce efficient cell death. Together with well-regulated controlled release design, this new type of MSN@Fe3O4 nanosystem can be considered as a new class of multifunctional nanodevice with combined high drug payload, tunable drug release, high cellular uptake efficiency, adjustable zero-to-sustain release simultaneously and nanoimaging modalities for biomedical applications.
9:00 PM - QQ9.30
Radiosensitizer-eluting Nanocoatings on Gold Fiducials for Biological In-situ Image Guided Radio Therapy (BIS-IGRT).
Dattatri Nagesha 1 , Rajiv Kumar 1 , Cassandra Stambaugh 1 , Dayane Tada 1 , Robert Cormack 2 , Mike Makrigiorgos 2 , Srinivas Sridhar 1
1 Physics, Northeastern University, Boston, Massachusetts, United States, 2 Radiation Oncology, Dana Farber Cancer Institute, Brigham and Women's Hospital, Boston, Massachusetts, United States
Show AbstractImage-guided radiation treatments (IGRT) routinely utilize radio-opaque implantable devices, such as fiducials or brachytherapy spacers, for improved spatial accuracy. Modifying IGRT fiducials, to provide in vivo localized delivery of radiosensitizer to a tumor in addition to guiding beam delivery, offers an opportunity to improve the therapeutic ratio of radiation therapy without introducing any additional patient interventions. This method of biological in-situ IGRT (BIS-IGRT) or dose painting of radiosensitizers from the gold fiducial markers can be facilitated through coatings of NPs and nanoporous polymer matrices that incorporate these radiosensitizers. In this work poly(D,L-lactic-co-glycolic acid) (PLGA) NPs were loaded with fluorescent Coumarin-6, serving as a model for a hydrophobic drug, in a biodegradable chitosan matrix. Through this experimental work the feasibility of constructing drug- loaded biocompatible polymer coated gold fiducials that are capable of releasing radio-sensitizer over a period of four weeks or more for BIS-IGRT was evaluated. Temporal release kinetics of the drug in buffer was carried out using fluorescence spectroscopy. The release of NPs from the matrix and the free drug from within the NPs were controlled by degradation rate of chitosan matrix and PLGA. The results show that dosage and rate of release of these radiosensitizers coated on gold fiducials can be precisely tailored to achieve the desired release profile for radiation therapy of cancer. This work was supported by IGERT Nanomedicine Science and Technology Program (NSF 0504331), Dana Farber Cancer Institute and Northeastern University.
9:00 PM - QQ9.31
Polycomplexation Between Poly(ethylene glycol) and Synthetic Tannins.
Omar Fisher 1 , Robert Langer 1 , Daniel Anderson 1
1 Koch Institute, MIT, Cambridge, Massachusetts, United States
Show AbstractTannins are a class of polyphenols that are commonly consumed in the human diet. They are known to precipitate poly(ethylene glycol) (PEG) from aqueous solution through the formation of hydrogen bonded polycomplexes. The lack of research on this phenomenon may be due to the difficulty in obtaining polyphenols of sufficiently high molecular weight and the instability of polyphenols. Polyphenols are uniquely attractive as complexing agents because of their relatively weak acidity. This makes them attractive for biomedical applications because their H-bonding is preserved well above physiological pH. The structure of hydrolysable tannins consists of phenolic moieties linked through depsidic bonds and conjugated through esters to a carbohydrate backbone. We have shown that two tannins, tannic acid and quebracho tannin, can form self-assembled nanoparticles when mixed with PEG. However, these are both hydrolytically and oxidatively unstable. Furthermore, commercially available tannins are heterogeneous plants extracts which provide no control over the size or structure of their phenolic constituents. We have synthesized synthetic polymers which mimic the structure of hydrolyzable tannins that lack unstable depsidic bonds, such as pentagalloylglucose. Pentagalloylglucose alone does not appear to form polycomplexes with PEG, most likely because it is below the minimum size needed for cooperative H-bonding. In order to make tannin mimics of higher molecular weight and with greater stability we attached galloyl and other phenol units to dextran backbones. By using dextran scaffolds with a range of molecular weights we created libraries of synthetic tannins. We used turbidity studies to characterize complexes formed between these polymers mixed with linear and branched PEGs. Polycomplex stability between synthetic tannins and PEG generally increased with molecular weight and branching. The use of multi-arm PEGs resulted in the spontaneous formation of stable nanoscale colloids which are potentially useful as nanoscale drug delivery agents.
9:00 PM - QQ9.34
Polymer-coated Silica Nanoparticles for Electromediated Gene Delivery.
Won Gu Lee 1
1 Mechanical Engineering, Kyung Hee University, Yongin, Gyeonggi, Korea (the Republic of)
Show AbstractIn this study, we present a role of polarized nanoparticles as engineered gene transporters that can enhance electromediated gene delivery. To validate its proof-of-concept, fluorescent poly (ethylene glycol) (PEG)-coated silica nanoparticles (SiNPs) with opposite polarities, SiNPs(RITC)-PEG/PTMA(+) and SiNPs(RITC)-PEG/PMP(-), are used. To investigate electroporative uptake directions of nanoparticles-gene complex, we employ microscale electroporation that can generate more symmetric and uniform electric field. The effect of polarities of nanoparticles on EGFP gene transfection efficiency in HeLa cells is measured by flow cytometry analysis. The results show that anionic nanoparticles hold potential as electromediated gene transporters at a low gene concentration level, compared to cationic nanoparticles. We furthermore believe that this finding can be potentially useful for developing a platform, which enables electroporation-based gene/drug delivery associated with functional nanoparticles.
9:00 PM - QQ9.35
The Modification of Cancer Vaccine Based on Metabolism Byproducts of Bacillus subtilis-7025 using Nanoparticles of Carbon and Silicium.
Liubov Sorokina 1 , Gennady Didenko 1 , Olexandr Golub 3 , Evgen Shpak 1 , Grigory Potebnya 1 , Oleg Lysenko 2 , Athanasios Mamalis 4
1 , R. E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, Kyiv Ukraine, 3 , Taras Shevchenko National University of Kyiv, Kyiv Ukraine, 2 , V. Bakul Institute for Superhard Materials, Kyiv Ukraine, 4 , Project Center for Nanotechnology and Advanced Engineering, NRC “Demokritos”, Athens Greece
Show AbstractThe new branch has been separated in the development of new anticancer drugs and cancer vaccines engineering that bases on the application of prospective conjugates or active compounds with adjuvant functions [1]. The sorption of biomolecules on solid surface makes an effect on the biological activity due to the changes in chemical and structural properties. The nanoparticles of carbon and silicium provide the possibility of using them as effective sorbents for vaccine components and facilitate the delivery of drugs, and at the same time these nanocompounds makes doses of the injected drug to reduce [2]. The active compound (AC) of glycoprotein nature with the cytotoxic activity towards the TC was isolated from the culture medium of Bacillus subtilis-7025 [3]. The aim of our study was to evaluate the effectiveness of the vaccine on the basis of isolated AC sorbed on the nanocompounds (NCs).The experiments were performed using Balb/c mice with inoculated sarcoma 37 tumors. Fullerene, aerosil, and fullerene chemically attached to aminopropilaerosil were used as nanosorbents. Cancer vaccine (CV) was prepared as described in [3]. The sorption of the CV on NCs took place during 10 minutes just before the injection. CV sorbed on NCs was injected in combination with peritoneal autologous macrophages (AM). Antitumor activity was evaluated using the indices of tumor growth (TG) dynamics, average life (AL) and the rate of antitumor immunity (the level of antibodies (LA) in blood, the activity of peritoneal macrophages, the direct cytotoxic activity of lymphocytes-CTL). Student’s t-test was used for evaluation of the differences reliability (at P<0.05).The significant delay in TG and the 1,5-3-fold increase of AL of mice treated with CV on NCs in combination with AM was shown. In 20% of tumor-bearing mice tumor regression was observed after the treatment with the complex CV-aerosil. It was shown that the activity of peritoneal macrophages on the 7th day after treatment for the all of experimental groups was increased. The results of immune-enzyme assay for antibodies against the tumor antigens indicated that after the 3rd vaccination the LA in the serum of treated with the complex CV-NCs-AM mice was exceeded the LA in the serum of control mice 4-fold. The CTL was increased till the 20th day after vaccination (in complex with chemically attached fullerene – 36%, in complex with aerosil – 32%) followed by decrease of CTL. Thus, the modification of cancer vaccines using nanomaterials and autologous macrophages increases their antitumor effectiveness significantly. References1. Cuenca AG, Jiang H, Hochwald SN, et al. // Cancer 2006; 107(3): 459-66.2. Bosi S, Da Ros T, Spalluto G, Prato M. // Eur J Med Chem 2003; 38(11–12): 913–23. 3. Potebnya GP, Semernikov VA, Lisovenko GS, Khutornoi SV, Tarasova TA. // Exp Oncol 1998; V.20: 143-147.
9:00 PM - QQ9.36
Efficiency of Cationic Rosette Nanotubes for siRNA Delivery.
Aws Alshamsan 1 2 , Mounir El Bakkari 1 3 , Hicham Fenniri 1 3
1 , National Institute for Nanotechnology (NINT-NRC), Edmonton, Alberta, Canada, 2 Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh Saudi Arabia, 3 Department of Chemistry, Faculty of Science, University of Alberta, Edmonton, Alberta, Canada
Show AbstractSmall interfering RNA (siRNA) has shown therapeutic potentials in animal models. However, the lack of optimum delivery system slowed the progress of siRNA technology from bench to bedside. We propose lysine-decorated rosette nanotubes (K-RNTs) as a mean for siRNA delivery. K-RNTs are superstructures that are based on the entropy-driven self-assembly of a synthetic self-complementary guanine-cytosine (G^C) motif. Cationic RNTs were generated by functionalization of G^C motifs with up to 15 L-lysine residues to a twin G^C motif (Kn.T), while siRNA binding capacity was determined on agarose gel by gel retardation assay. Up to K5.T, siRNA mobility was completely retarded as a function of oligolysine-chain length and mole ratio of Kn.T. Although siRNA binding was proportional to Kn.T ratio, incomplete retardation of siRNA mobility started to appear when the oligolysine chain was further elongated beyond K5.T. This suggests supramolecular assembly as a third factor for siRNA binding with Kn.T since K6.T-K15.T exhibit lower ability to form nanotubular structures as compared to K1.T-K5.T. To confirm this observation, we conducted a gel-retardation experiment where Kn.T binding to siRNA was compared to equivalent mole ratios of corresponding oligolysine without G^C motifs. Interestingly, no effective siRNA binding was noticed. Moreover, the binding capacities of our Kn.T systems were comparable in PBS and Tris-HCl (pH 7) to unbuffered water. With K12.T, siRNA complexation initiated spherical structure formation that was in a range of 200 nm. These nanospheres were internalized and retained by human umbilical vein endothelial cells and Caco-2 human colorectal adenocarcinoma cells for up to 72 h. Upon the internalization of K12.T/non-targeting siRNA complexes, no significant reduction in cell viability was noticed with both cell lines indicating the biocompatibility of these systems. Taken together, we anticipate these K-RNTs to be effective in the delivery of biologically-functional siRNA, which is currently being investigated in our lab.
9:00 PM - QQ9.37
Novel Polymer-polymer and Polymer-liposome Nanohybrid Systems as Potential Targeted Delivery Vehicles.
Suhair Sunoqrot 1 , Jin Woo Bae 1 , Su-Eon Jin 1 , Ying Liu 2 , Seungpyo Hong 1
1 Biopharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, United States, 2 Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois, United States
Show AbstractAlthough polycations have demonstrated potential as nonviral gene delivery vectors, high toxicity has hindered their applications in vivo due to the cationic surface that induces uncontrolled, spontaneous interactions with cells. Fine control over the cellular interactions of a potential gene delivery vector would be thus desirable. Herein we have designed novel nanohybrid systems (100-150 nm in diameter) that combine the polycations with protective outer layers consisting of biodegradable polymeric nanoparticles (NPs) or liposomes. The protective layers prevent the surface primary amine groups from fast exposure to biological substances, thereby reducing the toxicity as well as providing a control over cellular uptake kinetics. A commonly used gene delivery vector Polyethylenimine (PEI) conjugated with rhodamine (PEI-RHO) is selected as a multi-functional nanovector. The PEI-RHO conjugates were then encapsulated into: i) biodegradable polymeric nanoparticles (NPs) of either polylactide-co-glycolide (PLGA) or polyethylene oxide-b-polylactide (PEO-PLA) and ii) PEGylated anionic liposomes, resulting in three novel nanohybrid systems. The polymeric NP- and liposome-based systems were characterized and compared in terms of particle size, zeta potential, encapsulation/loading efficiency, in vitro release, and uptake kinetics by MCF-7 cells. Cytotoxicity of PEI was also determined at various concentrations and incubation times, and compared with that of the final nanohybrids. Through the nano-hybridization, cellular uptake and cytotoxicity of the nanohybrids were kinetically fine tuned. In addition, particle sizes of all nanohybrids were suitable for passive targeting. The results present a potential gene delivery platform with enhanced control over its biological interaction kinetics and cytotoxicity, along with passive targeting potential through size control.
9:00 PM - QQ9.38
Multi-segmented Nanorods for Thermo-sensitive Drug Carriers.
Hyuksang Yoo 1 , Shinyoung Park 1 , Ji Suk Choi 1 , Hyesung Kim 1 , Young Ju Son 1
1 , Kangwon National University, Chuncheon Korea (the Republic of)
Show AbstractA gold-nickel multi-segmented nanorod was fabricated by electrodeposition into an Al2O3 template with a pore diameter 100nm. A diameter of segment could be adjusted regulating of coulomb. A gold segment was chemically modified with Pluronic F-127 to encapsulate excessive amounts of doxorubicin around the nanorod and a nickel segment was decorated with folate to confer an active targeting moiety to the nanorod toward cancer cells. Thiol-modified doxorubicin was conjugated to gold segment and a carboxyl group of folate was attached to nickel segment. In Pluronic F-127 modified rods, doxorubicin was reversibly encapsulated to the rods according to temperature change from 4°C to 37°C. However, in unmodified rods, doxorubicin was bound to rods irreversible. Doxorubicin was maximally encapsulated around the modified nanorods at 37°C and a full extent of doxorubicin release was observed at 4°C. Further studies are required to determine amounts of drug loading according to gold segment length, targeting effects of folate. With this results, nanorods should be employed nanorods as multifunctional anti-cancer drug carriers.
9:00 PM - QQ9.39
Microspheres Encapsulating Stabilized Iron Oxide Nano Aggregate (SIONA) with mPEG-PCL Block Copolymer for Intestinal Imaging.
Hyuksang Yoo 1 , Young Ju Son 1 , Ji Suk Choi 1 , Hyesung Kim 1
1 , Kangwon National University, Chuncheon Korea (the Republic of)
Show AbstractStabilized iron oxide nano aggregate (SIONA) was prepared and subsequently encapsulated in pH-sensitive microspheres, which are expected to protect SIONA from gastric acid and be targeted small intestine. The synthesized methoxy poly(ethylene glycol)-poly (caprolactone) (mPEG-PCL) block copolymer in dichloromethane and FeCl2/FeCl3 dissolved in aqueous phase were subsequently added to the organic phase and ammonium hydroxide. Eudragit L100-55, pH-sensitive polymethacrylate polymer, and the mPEG-PCL-stabilized magnetic nanoaggregates in a methanol/acetone mixture (2:1) were slowly poured into mineral oil with 1% Span83. The mineral oil was washed off by n-hexane. In order to determine loading amounts of magnetite in the microsphere, Eudragit was dissolved in citric acid buffer (pH5.0) and magnetite was centrifuged and weighed. The microspheres were immersed in buffers with different pHs to determine the stabilization of microspheres. The amount of released magnetite or iron ions was spectrophotometrically measured. Iron solutions with different concentrations were employed as a standard curve. Compared to magnetite only, mPEG-PCL stabilized magnetite retained the original size for 2h in a dose dependent manner. Although the theoretical loading was kept at 20% (w/w), the actual loading amount was significantly decreased as the amount of block copolymer decreased. The block copolymer stabilized magnetite has high surface-to-volume ratios because magnetite aggregates were not formed.
9:00 PM - QQ9.4
Kilogram Quantity Production of Monodisperse Iron Oxide Nanoparticle and Size Controlled Preparation of MRI Contrast Agent using the Nanoparticle.
Bong-sik Jeon 1 , Eung-Gyu Kim 1 , Eun-Byul Kwon 1 , Juyoung Park 1 , Wan-Jae Myeong 1 , Taeg-hwan Hyeon 2
1 Nano R&D Group, Hanwha Chemical, Daejeon Korea (the Republic of), 2 , Seoul National University, Seoul Korea (the Republic of)
Show AbstractMonodisperse iron oxide nanoparticles with superparamagnetism attract a great deal of interest in biomedical application especially MRI contrast agent because particle diameter not only strictly determines the magnetic properties but also affects the relaxivity of MRI contrast agent. Thermal decomposition by heating-up seems to be the best method for the production of monodisperse nanoparticles in large scale. But to become industrially meaningful, it is essential of the nanoparticles to be prepared with large quantity. The nanoparticles synthesized by thermal decomposition method are usually coated by hydrophobic surfactant, so to apply them to MRI contrast agent it is crucial to make the particles be hydrophilic with biocompatibility. Other important things are the absorption, distribution, metabolism and excretion of MRI contrast agent in a living body, which are also strongly dependent on the size of the nanoparticles. In this study, production of monodisperse nanoparticles with kilogram quantity, preparation of size-controlled biocompatible nanocapsule using the iron oxide nanoparticles and superior MRI performance of the nanocapsule are reported.Semi-commercial plant including 100 liter volume reactor and specific control systems was designed based on the heating-up method. The plant was constructed and operated successfully and more than 1 kilogram of iron oxide nanoparticles could be prepared in a batch. The nanoparticles showed uniform-size and spherical-shape in TEM and DLS analysis. The coefficient of variance (Cv) of the nanoparticles is much below 10 %, which means they are extremely uniform.The nanoparticles prepared in the plant were encapsulated by PLGA via modified emulsification-diffusion method which uses co-solvent with high temperature. The shape and diameter of the capsules were also measured by DLS and TEM. Modified emulsification-diffusion technique could highly enhance the encapsulation efficiency and capsule size uniformity over the conventional method. It was also possible to precisely control the nanocapsule size below 100 nm with narrow size distribution and increase the encapsulation efficiency by simple process parameters such as the ratio between nanoparticles and PLGA. The magnetic relaxation experiments for the nanocapsules in vitro and in vivo were also carried out. The T2 relaxivity of as-prepared nanocapsules was higher than commercial T2 contrast agents and causes deeper signal drop in mouse MRI experiments. It was verified that there is no cytotoxicity in the range above 40 times of human dose by using HEK293 and HepG2 cell line.
9:00 PM - QQ9.40
Nano-scale Pillar Array for Differentiation of Human Mesenchymal Stem Cell.
Hyuksang Yoo 1 , Hye Sung Kim 1 , Ji Suk Choi 1 , Young Ju Son 1
1 , Kangwon National University, Chuncheon Korea (the Republic of)
Show AbstractCell adhesion to the extracellular matrix (ECM) is directly related to cell survival, migration, cell cycle progression and expression of differentiated phenotype. Therefore, cell behavior can be controlled by manipulating focal adhesion point because cell attachment is controlled by focal adhesion molecules such as fibronectin, laminin and integrin. In order to induce differentiation of stem cell, we prepared nano-scale pillar array modified with focal adhesion protein. The silicon wafer was spin coated with a positive photoresist ZEP 520A (ZEON Corp.) (4,000Å). Nanoscale features were patterned in the resist using e-beam lithography (EBL) (Elionix, ELS7000) (100eKV) then developed in O Xylene (30s) and rinsed with isopropyl alcohol (IPA) (30 s). The silicon wafer was then dry etched using a RIE(LAM corp. TCP9400DFM ). The silicon master was silanized with trichloro(1H, 1H, 2H, 2H-perfluorooctyl)silane in vapor phase to facilitate the release of the elastomer from the wafers after curing. Prepolymer of poly (dimethylsiloxane) (PDMS; sylgard 184, Dow-Coring), was poured over an array of holes on the master and cured at 85°C for 3h and then release from the master. This resulted in arrays of elastic PDMS pillars of 500nm diameter, a height of 1μm, and distances of 5, 10μm respectively.
9:00 PM - QQ9.41
Polymer Micelles with Calcium Phosphate Nanoshells for Smart Intracellular Drug Delivery Systems.
Hong Jae Lee 1 , Kyung Hyun Min 2 , Seo Young Jeong 2 , Sang Cheon Lee 1
1 School of dentisty, Kyung Hee University, Seoul Korea (the Republic of), 2 Departmemt of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul Korea (the Republic of)
Show AbstractSystematic incorporation of inorganic species into organic nanostructured materials has provided an important guidance for the novel design of multifunctional hybrid nanomaterials. We fabricated the robust hybrid nanocarriers based on spatially selective mineralized polymer micelles for the anticancer drug release at a specific cellular condition. Polymer micelles of poly(ethylene glycol)-poly(L-aspartic acid)-poly(L-phenylalanine) as core-shell-corona type nanotemplates for calcium phosphate (CaP) mineralization were prepared. Subsequently, Cy5.5, a near-infrared fluorescence (NIRF) dye, was conjugated to polymer micelles to monitor the in vivo biodistibution of mineralized micelles. Using doxorubicin (DOX)-loaded polymer micelles (DOX-PM), the mineralized nanocarriers (DOX-PM-CaP) were fabricated by calcium phosphate (CaP) deposition onto the PAsp middle shells. TEM images exhibited the formation of the inorganic CaP nanoshells on polymer micelle nanotemplates. DOX-PM-CaP in extracellular environments (pH 7.4, [Ca2+] = 2.0 mM) showed a retarded release pattern of DOX rather than DOX-PM. However, DOX-PM-CaP demonstrated the much faster DOX release at an intracellular lysosomal condition (pH 4.5, [Ca2+] = 0.1 mM), comparing to extracellular conditions. Calcium dissolution from mineralized micelles was more facilitated in the intracellular compartment than in the extracellular conditions. These results supported that the mineralized layer as a diffusion barrier would minimize the loss of the entrapped drug before reaching the target tissue, and selectively dissolve in lower pH and Ca2+ concentration of lysosomal compartments to facilitate intracellular drug release. For the assessment of in vivo therapeutic efficacy, we performed the biodistribution study using near-infrared imaging for tumor-bearing mice, and the prepared DOX-PM-CaP were successfully delivered to tumor site by enhanced permeability and retention effect. Furthermore, the tumor volume monitoring was conducted based on DOX-PM-CaP using tumor-bearing mice. Due to effective drug release from DOX-PM-CaP at tumor region, the growth of tumor was remarkably inhibited, compared with control groups. The mineralized nanocarriers may provide a platform technology for the generation of many high-performance nanocarriers for cancer therapy. Acknowledgement This research was supported by a grant (code #: 2010K000296) from ‘Center for Nanostructured Materials Technology’ under ‘21st Century Frontier R&D Programs’ of the Ministry of Education, Science and Technology, Korea.
9:00 PM - QQ9.5
Controlled Clustering of Superparamagnetic Nanoparticles in Fluorescent Nanogels as Highly Effective T2-Weighted MRI Contrast Agents and Optical Probes.
Eugene Choo 1 , Xiaosheng Tang 1 , Yang Sheng 1 , Borys Shuter 2 , Jun Min Xue 1
1 Materials Science and Engineering, National University of Singapore, Singapore Singapore, 2 Yong Loo Lin School of Medicine, National University of Singapore, Singapoer Singapore
Show AbstractSpherical superparamagnetic iron oxide nanoclusters with well-controlled shape and size are fabricated for potential application as magnetic resonance imaging (MRI) contrast agents. MRI is an advanced imaging technique that is gaining popularity because it is non-invasive and provides high spatial resolution and penetration depth for detailed internal cross-sectional images of biological tissues. In order to improve feature resolution in MRI, contrast agents are being developed. Superparamagnetic iron oxide nanoparticles (SPIONs), in particular, are currently the front-runners as T2 contrast agents. However, the ability to further improve the effectiveness of T2 contrast agents is limited by the magnetic moment of the SPION, which is limited by the critical size that drives the superparamagnetic-ferromagnetic transition. Alternatively, the effectiveness of T2 contrast agents can be improved by the formation of secondary structures via the self-organization of SPIONs to form large magnetic centers. The establishment of secondary structures holds two key advantages: (1) to collectively combine properties of individual nanoparticles, and (2) retain the unique superparamagnetic property. Nanoassemblies of SPIONs have been reported to be more effective in reducing spin-spin relaxation times as compared to the individual magnetic SPIONs. To take advantage of this interesting property, the bottom-up organization of SPIONs was investigated. SPIONs are clustered in a controlled manner, through a nanoemulsion/solvent evaporation technique, using a nanogel as the spherical matrix to form superparamagnetic nanoclusters. Under appropriate emulsion conditions, the hydrodynamic size is easily controlled to <200 nm with good size uniformity, which are very important properties for intravenous applications. The nanogel material is an amphiphilic brush-structured copolymer that not only forms a protective coating over the SPIONs but also confers excellent water dispersibility and colloidal stability. The process conditions are also very mild and easily upscaled, which make it a highly practical and commercially viable option. MRI measurements clearly show substantial improvement as the packing density of the magnetic cores increases. Further functionality is introduced by modifying the nanogel with fluorescein for optical tagging of cells, which is very useful because optical imaging can be utilized in conjunction with MRI for bimodal imaging purposes. This work offers a robust and versatile platform for the development of multifunctional spherical magnetic clusters for MRI contrast agents, with the potential for multimodal imaging applications.
9:00 PM - QQ9.6
Magnetism in Luteinizing Hormone and Releasing Hormone (LHRH) Bound Gold Coated SPIONs – Novel Nanomaterials for Hyperthermia.
Faruq Mohammad 1 2 , Balaji Gopalan 1 , Andrew Weber 1 , Rao Uppu 2 , Kumar Challa 1
1 Center for Advanced Microstructures & Devices, Louisiana State University, Baton Rouge, Louisiana, United States, 2 Environmental Toxicology, Southern University and A&M College, Baton Rouge, Louisiana, United States
Show Abstract We report synthesis of gold coated superparamagnetic iron oxide nanoparticles (SPIONs) of ~ 6.3 nm size and their characterization by a variety of techniques like XRD, HRTEM, EDX, SAXS, UV-Vis, FT-IR and XPS. The gold coated SPIONs were step-wise bio-functionalized with leutenizing hormone and releasing hormone (LHRH) through cysteamine linker. On application of low frequency oscillating magnetic fields (44 – 430 Hz), a four- to-five-fold increase in the amount of heat released with gold-coated SPIONs (6.3 nm size) was observed in comparison with SPIONs (5.4 nm size) providing evidence that gold nanoshell enhances hyperthermia of SPIONs. The hyperthermia of gold nanoshells was also found to be influenced by frequencies of oscillating magnetic field, concentration and solvent. A detailed magnetic analysis of SPIONs, gold coated SPIONs, cysteamine bound gold coated SPIONs and LHRH-cysteamine bound gold coated SPIONs reveal a step-wise changing of magnetic behavior from super paramagnetic to permanent magnetism at room temperature. The observed permanent magnetism at room temperature in LHRH-capped gold nanoshells and enhanced hyperthermia on coating SPIONS with gold shell provides opportunities to extend fundamental investigations of permanent magnetism to other novel nanostructures and biofunctionalized nano gold architectures, simultaneously opening the way to newer applications, especially those in biomedicine.
9:00 PM - QQ9.7
A Modified Solvothermal Synthesis of Fe3O4 Nanospheres and Nanosheets with High Magnetization and Excellent Dispersibility and the Exploration for its Mechanism.
Lin Zhuang 1 , Yongxin Zhao 1 , Jinhua Liang 1 , Hui Shen 1
1 , Sun Yat-sen University, Guangzhou China
Show AbstractFe3O4 nanospheres and nanosheets with high magnetization and excellent dispersibility have been fabricated by a modified solvothermal method. The size of formed nanospheres decreases as the EG/DEG ratio decreases. DEG has a stronger affinity to Fe3+ ions .The viscosity of the solvent increases as the portion of DEG increases and therefore the coefficient of diffusion of the species in the reaction system decreases which leads to smaller grain size of the Fe3O4. When the EG/DEG ratio decreases to 0/40 DEG, Fe3+ form a steady and dissolvable composition and growing of crystal plane is inhibited. A transformation of Fe3O4 from nanospheres to nanosheets appears.
9:00 PM - QQ9.8
Decreasing Biofilm Formation Through the Use of Superparamagnetic Iron Oxide Nanoparticles (SPION).
Erik Taylor 1
1 Biomedical Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractSummaryRecalcitrant infection has been reported on an array of implantable devices including joint prostheses, central venous catheters, endotracheal tubes, mechanical heart valves, and others [1]. Moreover, it is clear that antibiotic resistant bacteria are spreading in the hospital setting. The inability of antibiotic treatment to kill these resistant infections requires an alternative.In search of an effective approach for bacteria treatment, the goal of this proposal is to explore the use of superparamagnetic iron oxide nanoparticles (SPION) to treat infection on biomedical devices. In this study, SPION were coated with dimercaptosuccinic acid (DMSA) providing a multifunctional linker to coat with iron, zinc, and silver to improve antibacterial activity, which can also be used to further link antibodies, such as anti-protein A, via sulphur-maleimide interactions to target Staphylococcus (S.) aureus in biofilms. Once at the target site, SPION could offer antibacterial properties, therapeutic feedback (via MRI), and even delivery of other drugs.MethodsTo produce SPION, synthesis was carried out by refluxing iron(III)acetylacetone in triethylene glycol. After cooling, DMSA was added, and further conjugated with AgNO3, ZnCl2, or FeCl3. SPION were characterized with a Philips JOEL 140 kV transmission electron microscopy (TEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) to confirm metal conjugation.Bacteria used were S. aureus (ATCC #25923) obtained in freeze-dried form, rehydrated in tryptic soy broth (TSB), incubated (37 ° C, 5% CO2, humidified environment), and frozen prior to streaking. A second 18 hour culture was used to establish biofilms in 96 well plates. Biofilm formation was analyzed using a 1% crystal violet stain at 562 nm. For the biofilm magnetic uptake assay, a neodymium magnet was used to regionalize SPION, and then stained with Prussian blue to visualize the amount of iron deposited.Results & ConclusionTEM analysis demonstrated SPION of small size (about 10 nm in diameter) with a narrow range of size dispersion. Zn and Ag coatings were confirmed by ICP-AES. All SPION at 1 mg/ml decreased the amount of bacterial biomass at 48 hours, while only zinc added an improved benefit over the uncoated SPION. Magnetic field exposure enhanced biofilm uptake of SPION after only 20 minutes.The SPION designed here were compatible for coating with various antibacterial metals (such as zinc and silver), while SPION alone also demonstrated significant anti-biofilm activity against an existing biofilm. SPION also proved to be useful for control and direction into biofilms in the presence of a magnetic field. These results help to confirm that SPION could have multiple uses during device related infections for biofilm treatment, magnetic direction, and antibacterial delivery.References:[1] Donlan, R.M., Emerg. Infect. Dis., 2001.
9:00 PM - QQ9.9
Composite Magnetic Nanoparticles Designed for Maximal Transverse Relaxivity and Multifunctionality.
Huilin Shao 1 , Tae-Joon Yoon 1 2 , Ralph Weissleder 1 3 , Hakho Lee 1
1 Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States, 2 Department of Applied Bioscience, CHA University, Seoul Korea (the Republic of), 3 Systems Biology, Harvard Medical School, Boston, Massachusetts, United States
Show AbstractMultifunctional magnetic nanoparticles are promising new material in biomedical research and applications. Magnetic nanoparticles (MNPs), with their high intrinsic transverse relaxivity (r2) to accelerate the spin-spin relaxation in water molecules, are attractive image contrast agents for magnetic resonance imaging. When integrated with additional imaging probes, MNPs can improve diagnostic accuracy by enabling multimodal imaging; when loaded with drugs, MNPS can be used for disease treatment as well as its detection. Here we report a new strategy to prepare multifunctional MNPs that can achieve maximal r2 relaxivity. In this approach, small MNPs are assembled into nanoscale clusters and encapsulated inside a silica shell with other functional materials. The composite particle acquires high r2 relaxivity due to its large magnetic core. Furthermore, by optimizing the shell thickness, the r2 relaxivity can approach the maximum value as predicted by a theoretical model. As a specific example, we have synthesized MNPs for magnetic resonance and fluorescent imaging/sensing. We embedded a cluster of Mn-doped ferrite particles in a silica shell infused with fluorescent molecules. The resulting MNPs exhibited high r2 (695 s-1 mM-1 [metal]), close to the theoretical limit (759 s-1 mM-1 [metal]), and also showed excellent photostability. We applied the particles for the sensitive, NMR-based detection of biomarkers and mammalian cells in vivo. Dual imaging capacity was demonstrated by magnetic resonance and fluorescent imaging in vivo.
Symposium Organizers
Larry A. Nagahara National Cancer Institute
Robert Sinclair Stanford University
Rashid Bashir University of Illinois, Urbana-Champaign
Thomas Thundat Oak Ridge National Laboratory
Wenbin Lin University of North Carolina, Chapel Hill
QQ10: Nanomaterials Formulation, Targeting, and Interactions for Biomedical Applications
Session Chairs
Wenbin Lin
Thomas Thundat
Thursday AM, December 02, 2010
Grand Ballroom (Sheraton)
9:00 AM - QQ10.1
Biomimetic Nanostructured Particles for Molecular Recognition by Molecular Imprinting.
Guenter Tovar 1 2 , Klaus Niedergall 2 , Daria Wojciukiewicz 2 , Tino Schreiber 2 , Carmen Gruber-Traub 1 , Achim Weber 1 , Thomas Hirth 1 2
1 Interface and Material Sciences, Fraunhofer IGB, Stuttgart Germany, 2 Institute for Interfacial Engineering, University of Stuttgart, Stuttgart Germany
Show AbstractCommunication of living systems is done by molecular recognition. The biomimetic nanoparticles described here, possess such molecularly recognizing properties. Synthetic molecularly recognising nanoparticles were prepared by a cooperative chemical reaction which evokes the formation of specific molecular binding sites at the surface of copolymer nanoparticles. Such synthetic receptors may be employed e.g. as specific absorbers to remove micropollutants from the drinking water cycle or as functional units of a biosensor. The talk will highlight molecular imprinting of polymers(MIP) as a highly attractive route to synthesize nanostructured artificial receptors which combine the specificity of biological binding sites with the chemical stability of synthetic materials. Selective molecular binding sites are induced in a growing crosslinked polymeric material by template interaction of a non-polymerizing agent which interact noncovalently with specific parts in the polymer. The templates are washed from the generated polymer monoliths and the induced artificial binding sites can be applied for molecular recognition reactions. Nanostructured MIP monoliths (nanoMIP) were prepared by a modified miniemulsion polymerisation technique, where the monomer, the template, the cross-linker, and the initiator are reacted in the droplet cavities of an emulsion. The reaction, although complex, runs in a single reaction chamber and in a single-step chemical process. Thus a variety of active agents ranging from low molecular weight drugs to peptides, proteins and biomacromolecules can be imprinted. These nanoMIP dispose of the high surface area of nanostructrued materials and are thus highly attractive for use as specifically absorbing material. Moreover, the nanoMIP synthesis overcomes some crucial limitations of the preparation of imprinted material such as chemical inhomogeneity of a molecular imprinted polymeric matrix. The technique of miniemulsion polymerization results in particles with typical sizes between 50 nm and 300 nm. Besides classic miniemulsion polymerization (hydrophobic phase emulsified in hydrophilic phase – here water), a MIP technique also based on inverse miniemulsion polymerization is established. Thus, possible templates can be chosen from the full range of hydrophilic over amphiphilic to hydrophobic molecules. Additives like inorganic nanocrystals or organic fluorophores can be easily added to polymerization process. Thus nanostructrured hybrid-materials with multiple properties (fluorescence, magnetism) and specific binding sites are easily designed as valuable material in modern bio-analytics and diagnostics as well as in down stream processing in chemical and pharmaceutical industry. Widespread use in applications ranging from medical technology to environmental technology can be envisaged with the approach and will be discussed.
9:15 AM - QQ10.2
Moleculary Imprinted Polypyrrole for the Regulation of L-glutmate in Physiological Solutions.
Elizabeth von Hauff 1 , Ivan Chernov 1 , Juergen Parisi 1
1 Institute of Physics, Energy and Semiconductor Research Laboratory, University of Oldenburg, Oldenburg Germany
Show AbstractIn this study we present an electrochemical “molecular switch” for the regulation of biomolecules in physiological pH solutions. Molecularly imprinted polymers for the uptake and release of the neural transmitter L-glutamate were fabricated using polpyrrole (PPy). PPy was doped with L-glutamate during electrochemically deposition in a three electrode cell on gold electrodes. In previous studies we were able to demonstrate the fabrication of high quality, reproducible, L-glutamate doped PPy films [1,2,3]. The PPy layers were electrically degraded (overoxidized) after deposition in a controlled manner to expel the glutamate anion and create molecularly selective layers [4,5] which still adhered to the working electrode surface. The voltage regulated enantioselective uptake and release of L-glutamate was demonstrated in neutral pH solutions [3]. Here we present results from investigations to determine the concentration of glutamate which can be regulated by the device, as well as the efficiency and reproducibility of the uptake and release process. To gain a better understanding of the binding mechanism of the L-glutamate in the polymer film, the structure and the morphology of the film were investigated before and after overoxidization.[1]E. von Hauff, J. Parisi, R. Weiler, Zeitschrift Naturforsch. A, 63a (2008), 359.[2]Y. V. Meteleva-Fischer, E. von Hauff, J. Parisi, J. Appl. Polymer Sci., 114, 4051 (2009)[3]E. von Hauff, K. Fuchs, J. Parisi, R. Weiler, C. Burkhardt, U. Kraushaar, E. Guenther, Biosensors & Biomaterials, accepted.[4]B. Deore, Z. Chen, T. Nagaoka, ANALYTICAL SCIENCES, 15, 827–828, (1999).[5]V. Syritski, J. Reut, A. Menaker, R. E. Gyurcsányi, A. Öpik, ELECTROCHIMICA ACTA, 53, 2729 (2008).
9:30 AM - **QQ10.3
Lipid-polymer Hybrid Nanocarriers for Targeted and Controlled Drug Delivery.
Liangfang Zhang 1 2
1 Department of Nanoengineering, University of California San Diego, La Jolla, California, United States, 2 Moores Cancer Center, University of California San Diego, La Jolla, California, United States
Show AbstractLipid-polymer hybrid nanocarriers are synthesized through a single-step self-assembly process. The nanocarriers are comprised of four components: (a) a biodegradable polymeric core that can carry bioactive drugs with high loading yield and release the drugs at a controllable rate; (b) a lipid monolayer shell that can prevent the carried drugs from freely diffusing out of the nanocarriers and reduce water penetration rate into the nanocarriers; (c) a stealth material that allow the carriers to evade recognition by immune system components and increase their systemic circulation lifetime; and (d) a targeting ligand that specifically binds to target diseased cells. As an example, using poly D,L-lactic-co-glycolic acid (PLGA) polymer as the core, lecithin monolayer as the lipid shell, polyethylene glycol (PEG) as the stealth material, and a monoclonal half-antibody (mhAb) that binds to the carcinoembryonic antigen (CEA) as the targeting ligand, we prepared half-antibody functionalized lipid-PLGA hybrid nanocarriers for targeted drug delivery to pancreatic cancer cells that over-express the CEA antigen. The resulting hybrid drug nanocarriers are systemically characterized and evaluated regarding their biocompatibility, large-scale fabrication ability, drug carrying capacity, drug release kinetics, systemic circulation lifetime, and tumor homing properties.
10:00 AM - **QQ10.4
Development of Smart Molecules for Targeted Delivery of Nanoparticles.
Rihe Liu 1
1 Eshelman School of Pharmacy and Carolina Center for Genome Sciences, UNC Chapel Hill, Chapel Hill, North Carolina, United States
Show AbstractOne major challenge in cancer nanotechnology is how to selectively deliver nanofunctional materials to diseased tissues. Targeting ligands that confer 'smartness' to nanoparticles play a vital role in the targeted delivery of nanoparticles to cancer cells. This talk will discuss the use of directed molecular evolution approaches to the systematic development of novel targeting ligands (smart molecules), including engineered protein domains and nuclease-resistant nucleic acid aptamers, which recognize and target extracellular cancer biomarkers with desired affinity, avidity, multispecificity, low manufacturing costs, and compatibility for conjugation with nanofunctional materials.
11:00 AM - **QQ10.5
Zwitterionic-based Nanoparticles for Drug/Drug Delivery and Diagnostics.
Shaoyi Jiang 1
1 Chemical Engineering & Bioengineering, University of Washington, Seattle, Washington, United States
Show AbstractZwitterionic polymers such as poly(carboxybetaine) (PCB) have shown excellent stealth and functioanlization properties. In this work, I will review our recent effort to develop pCB-based nanoparticles (NPs) for drug/gene delivery and diagnostics. These NPs are formed from poly(lactic-co-glycolic acid) (PLGA)-PCB block copolymers or phospholipid-PCB conjugates. pCB is also used to modify therapeutic proteins and diagnostic agents such as iron oxide NPs. Furthermore, hydrolysable positively charged pCB ester is used to condense negatively charged DNA, which is released upon the hydrolysis of pCB ester. Molecular recognition elements are attached directly onto these pCB-based NPs via conventional NHS/EDC chemistry since pCB can do both jobs (i.e., nonfouling and functionalization) in one material. The physical, chemical, and biological properties of these NPs are characterized, such as their stability in 100% blood serum and plasma and their circulation time and bio-distribution in vivo. Results show that pCB-based NPs have many unique properties that other carriers do not have and thus are excellent alternatives to poly(ethylene glycol) (PEG)-based NPs for a broad range of applications.
11:30 AM - QQ10.6
Effect of Gold Nanoparticle Morphology on Adsorbed Protein Structure and Function.
Jennifer Gagner 1 2 , Richard Siegel 1 2 , Jonathan Dordick 1 3
1 Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Materials Science & Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 3 Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States
Show AbstractRecent developments in nanomaterial synthesis and processing have led to precise control of nanoparticle morphology and structure, giving rise to many biomedical applications not previously accessible. Many applications rely on specific, protein-mediated interactions with biological systems in the form of covalently attached or physically adsorbed proteins on the nanoparticle (NP) surface. It is, therefore, essential to develop a comprehensive understanding of how protein binding, structure and function are affected by NP characteristics such as size, curvature, morphology, crystal structure, and surface ligands. The current study examines the role of several of these nanoparticle characteristics on adsorbed proteins. Using gold nanospheres, nanorods, and nanocubes capped with 16-mercaptohexadecanoic acid, the effect on the structure and activity of lysozyme and α-chymotrypsin is explored. Particle populations are thoroughly characterized through electron microscopy (TEM), inductively coupled plasma mass spectroscopy, and Fourier transform IR analysis. Global changes in protein structure are monitored through circular dichroism and activity assays. Additional TEM, as well as atomic force microscopy, is used to determine the placement of the protein adsorption on the surface of the NP, and isothermal titration calorimetry is used to elucidate the nature of the binding interaction of the protein to the particle.Though many current studies focus primarily on exploiting NP material properties for biomedical applications, insufficient identification and understanding of the variables and effects involved at the protein-NP interface hinder the development of safe practical applications. Fundamental understanding of how these factors affect protein structure and function will assist in the strategic engineering of protein-NP conjugates for a variety of important biomedical applications.This work was supported by the US National Science Foundation under Grant No. DMR-0642573.
11:45 AM - QQ10.7
Nano-patterned Brushes: A Novel Tool for Tuning Precise Protein and Cell Adhesion.
Saugata Gon 1 , Maria Santore 2
1 Chemical Engineering, UMass Amherst, Amherst, Massachusetts, United States, 2 Dept. of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts, United States
Show AbstractSurfaces patterned with bio-molecular targeting agents are conventionally used for highly-specific protein and cell adhesion. This presentation explores an alternative approach: Instead of using specific bio-molecular targeting groups, small adhesive elements are placed on a surface randomly, with the rest of the surface rendered non-adhesive. While the adhesive elements themselves, for instance in solution, might exhibit only mild selectivity for various compounds within an analyte suspension, selective adhesion of targeted objects results from other mechanisms. These include recognition of lengthscales of the surface distribution of adhesive elements, along with the competition between attractions and repulsions between various species in the suspension and different parts of the collecting surface. The resulting binding selectivity can be quite sharp; however, one cannot generally specify adhesion of a single target from a complex analyte solution: Different components will be adhered, sharply, with changes in collector composition. An advantage, of this approach, however, lies in its simplicity and cost effectiveness. This presentation demonstrates these principles using a system in which cationic poly-L-lysine (PLL) patches (10 nm) are deposited randomly on a silica substrate and the remaining surface is passivated with a bio-compatible PEG brush. TIRF microscopy revealed that the patches were randomly arranged, not clustered. By precisely controlling the number of patches per unit area, we achieved sharp selectivity for adhesion of proteins and bacterial cells. For instance, it was found that a critical density of patches near 1500/μm2 was required for fibrinogen adsorption while a greater density (3500 patches/μm2) comprised the threshold for albumin , as measured by optical reflectometry. Surface compositions between these two thresholds discriminated binding of the two proteins, as demonstrated by Total Internal Reflectance Fluorescence. For some backfill brush architectures, the spacing between the patches at the threshold for protein capture clearly corresponded to the major dimension of the target protein, for instance fibrinogen’s 47 nm length. For more dense PEG brush backfills however, larger adhesion thresholds (4200 patches/μm2, for fibrinogen adhesion) were observed, corresponding to tighter patch arrangements and multivalent interactions between target proteins and adhesive surface elements. The surfaces also demonstrated sharp adhesion thresholds for S. Aureus bacteria, below those for the capture of proteins. Thus bacteria may be captured while proteins are rejected from these surfaces, and there may be potential to discriminate different bacterial types. Hence these novel surface architectures show promise of providing an alternative to chromatographic separation process, useful for protein and cell separation and diagnostics.
12:00 PM - QQ10.8
Enhancement of Protein Delivery and Immune Response through the Skin Using a Solid-in-oil Dispersion of Gold Nanorods.
Dakrong Pissuwan 1 , Keisuke Nose 1 , Ryohsuke Kurihara 1 , Kenji Kaneko 2 , Yoshiro Tahara 1 , Noriho Kamiya 1 3 , Masahiro Goto 1 3 , Yoshiki Katayama 1 3 , Takuro Niidome 1 3 4
1 Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka Japan, 2 Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka Japan, 3 Centre for Future Chemistry, Kyushu University, Fukuoka Japan, 4 PRESTO, Japan Science and Technology Corporation, Kawaguchi, Saitama Japan
Show AbstractTransdermal delivery is an attractive route for protein/drug delivery as it reduces the systematic toxicity that may occur with oral or intravenous administrations. For effective transdermal delivery, the protein/drug must be capable to pass through the skin barrier and attain the specific target. Recently, there has been reported a novel technique using a solid-in-oil dispersion (Tahara et al., J. Controlled Release., 131, 14-18, 2008) to enhance the permeation of proteins into skin. However, using this method to deliver a high molecular weight protein is still limited by the low permeability of the stratum corneum (SC). We then further developed this method by combining gold nanorods with solid-in-oil dispersions to enhance the skin permeation of large proteins and induce an immune response through the skin. We investigated the permeation of a large model protein, ovalbumin (MW ~45 kDa), into mouse skins using a Franz diffusion cell system. Mouse skins were treated with the solid-in-oil dispersion of gold nanorods, then irradiated by near infrared (NIR) light at a power density of 6 W/cm2 and further incubated for 12 h. The greater enhancement effect of protein delivery was observed after the treatment. This implies that the SC layer was partly ablated by a photothermal effect of gold nanorods that had been applied to the skin. We also studied the immune response by skin vaccination in vivo. The production of anti-ovalbumin antibodies in the serum of mice treated with a solid-in-oil dispersion plus NIR light irradiation of gold nanorods was 5 times higher than that of treatment with the original form of the solid-in-oil dispersion without gold nanorods.
These results show that the combination of gold nanorods in the solid-in-oil dispersion provides higher efficiency for a large protein (ovalbumin) delivery through the skin than the original formulation itself. Our approach therefore offers a new opportunity for transdermal delivery and skin vaccination system of high molecular proteins/drugs.
12:15 PM - QQ10.9
Design and Evaluation of Synthetic Amphiphilic Peptide as Antimicrobial Agents.
Nikken Wiradharma 1 , Ulung Khoe 1 , Charlotte Hausser 1 , Shuguang Zhang 1 , Yi-Yan Yang 1
1 , Institute of Bioengineering and Nanotechnology, Singapore Singapore
Show AbstractDrug resistance developed from pathogenic microorganisms against conventional small molecular antibiotics has presented an opportunity for development of macromolecular membranolytic substances as a new class of antibiotics. Biologically active peptides derived from innate immune system from various species have been reported as antimicrobial agents since several decades ago. Most of such peptides have a length of 16-44 amino acid residues, and can form α-helix secondary structure in a biological membrane-like environment, such as aqueous SDS or trifluoroethanol solutions. A common similarity also exists among those peptides as being both amphiphilic and cationic. In this study we present a simple de novo approach to design short synthetic antimicrobial peptides. These peptides have a general sequence of (XXYY)n, where X and Y are hydrophobic and hydrophilic amino acids, respectively. The aim of this study was to vary all X, Y, and n systematically so that α-helix conformation could be formed in membrane-like environment with a segregated cationic and hydrophobic region in the helixes, in order to achieve a desirable antimicrobial property with minimal hemolytic activity. Antimicrobial peptides were tested against Gram-positive bacteria Bacillus subtilis, Gram-negative bacteria Escherichia coli, and yeast Candida albicans. Most of the peptides having three repeat units (n=3) were effective against Gram-positive bacteria with more than 10 times selectivity towards bacterial cells over mammalian red blood cells. In addition, against yeast Candida albicans, these peptides were also effective at minimum inhibitory concentration of around 3-4 times lower than the 50% hemolytic concentration. Immunogenicity of these peptides was also tested by measuring the level of interferon-α and -γ (IFN-α and IFN-γ) secretions by Human monocytes upon treatment with the peptides. Level of IFN expressions in vitro remains insignificant, suggesting a potentially safe use of these peptides for antimibcrobial agent, without unnecessarily triggering non-specific immune response systemically. These peptides therefore form a promising synthetic class of short designer peptide amphiphiles for antimicrobial agents.
QQ11: Characterization and Translation of Nanomaterials for Biomedical Applications
Session Chairs
Larry Nagahara
Robert Sinclair
Thursday PM, December 02, 2010
Grand Ballroom (Sheraton)
2:30 PM - QQ11.1
Enhanced Bone Cell Response on Zirconium Oxide Nanotube Surface.
Christine Frandsen 1 , Karla Brammer 1 , Sungho Jin 1
1 Materials Science and Engineering, University of California, San Diego, La Jolla, California, United States
Show AbstractElectrochemical formation of tunable nanoscale oxide layers on biomedical metallic and alloy surfaces has recently drawn much attention in biomaterials research. In this study, we report on the bio-feasibility of a unique vertically aligned, laterally spaced nanotube nanostructure made of zirconium oxide (ZrO2) fabricated by anodization. The growth, morphology, and functionality of osteoblasts, or bone cells, cultured on ZrO2 nanotubes have been investigated. The initial cell response of adhesion and spreading was considerably improved on the nanotube surface as compared to a flat zirconium (Zr) surface without a nanostructure. The morphology of the adhered cells on the nanotube surface elicited a highly organized cytoskeleton with crisscross pattern actin, which was lacking on the flat Zr. Increased alkaline phosphatase levels, indicative of increased bone forming ability, and the formation of a concentrated calcified extracellular matrix implied improved osteoblast functionality and mineralization on the nanotube substrate, which was not observed on the flat Zr. This in vitro study shows that ZrO2 nanotubes as a biomedical material surface is highly promising because of its large surface area and unique nanoscale geometry which enhanced the osteoblast response and apparent role in providing a platform for bone growth.
2:45 PM - QQ11.2
Comparison of the Efficacy of Chemical and Nanoparticles-based Disinfectants on Escherichia coli as Model Organism.
Karthik Chamakura 1 , Rafael Perez-Ballestero 2 , Jingbo Liu 1 , Sajid Bashir 1
1 Chemistry, Texas A&M University-Kingsville, Kingsville, Texas, United States, 2 Biological and Health Sciences, Texas A&M University-Kingsville, Kingsville, Texas, United States
Show AbstractThe development of stable nanoparticles (NPs) had led to a surge of research into the mechanism, efficacy and appropriate protocols for utilization of NPs in disinfection of drinking water. However, comparative research into efficacy of chemicals versus nanoparticles disinfectants and appropriate protocols has not been developed. We offer a comparative evaluation of common disinfectants compared with silver (Ag) NPs. Phenol was used as a reference disinfectant for the determination of minimal bactericidal concentration (MBC).Escherichia coli (E. coli) was treated with various concentrations of two common disinfectants, phenol and sodium hypochlorite, and then compared with the bactericidal activity of Ag-NPs. The bactericidal activity of the three agents was assessed by culturing samples after two time periods. Phenol showed a minimal inhibition of 64 parts-per-thousand (ppt) for the 10 minute and 10 parts-per-million (ppm) for the 2 h treatment respectively. Similarly, sodium hypochlorite showed a MBC of 4,000 for the 10 minute and 10,000 for the 2 hr treatment respectively. E. coli were treated with four different Ag-NPs, which were prepared using the reducing agent sodium citrate or dimethylamine boron (DMAB) at 1:1, 1:2 and 1:4 molar ratios of Ag to reducing agent, respectively. Bactericidal activity was assessed by culturing samples after 2 h of treatment. The Ag-NPs prepared with either a 1:1 molar ratio of Ag to citrate or DMAB showed similar MBC of 40 ppm for the 2 h treatment. The Ag-NPs prepared with a 1:2 molar ratio of Ag to DMAB showed the highest bactericidal activity, resulting in a MBC of 10 ppm for the 2 h treatment. The differences of activities among the different preparations of AgNP could be due to differences in the average size of the nanoparticles or a lower tendency of nanoparticles aggregation. Colloidal suspensions of smaller NPs would offer higher reactive surface for the disinfectant activity. Similar results were observed except that 1:2 AgNP:Citrate and 1:1 AgNP:DMAB / 1:2 AgNP:DMAB proved to be the most effective formulations in terms of lowest concentration to kill 100% of the E. coli cells. Phase contrast optical microscopy indicated that the E. coli cell integrity was unaffected, confirmed by scanning electron micrographs. Energy dispersive spectroscopy of the E. coli cellular region indicated no discreet silver particles, suggesting disruption of the cellular membrane potential rather than cell membrane disruption. Lastly, the persistence of both types of disinfectants was examined. E. coli were treated with various concentrations of Ag-NPs and bactericidal activity was assessed by culturing samples after 2, 4, 6 and 8 h of treatment. The Ag-NPs showed persistent antimicrobial activity through the treatment period, resulting in significantly lower MBC with longer treatment times
3:00 PM - **QQ11.3
Bridging the Valley of Death: Resources for Accelerated Clinical Translation of Cancer Nanomedicine.
Anil Patri 1
1 Nanotechnology Characterization Laboratory, National Cancer Institute at Frederick (SAIC Frederick), Frederick, Maryland, United States
Show AbstractPromising drug discoveries in basic research often do not make it into clinics due to a lack of adequate resources for advanced preclinical assessment. This “valley of death” can be a significant stumbling block because it can be cost-prohibitive in early drug development when resources may be scarce. This is especially true for nanomedicines, which, due to their compositional complexity, may require more extensive characterization than small-molecule drugs. The progress of such therapies from the early research stage through preclinical development requires a collaborative effort with multi-disciplinary teams that leverage resources from government, industry, and academia. Realizing the potential of nanotechnology-based technologies for cancer treatment and diagnosis, the National Cancer Institute (NCI) established the Nanotechnology Characterization Laboratory (NCL) to accelerate the clinical translation of urgently needed cancer therapies. A multi-agency collaborative effort between the NCI, the National Institute of Standards and Technology (NIST) and the U.S. Food and Drug Administration (FDA), the NCL is a unique resource that provides advice and support throughout the preclinical testing process. Materials accepted into the NCL are characterized in a standardized analytical cascade that includes nanomaterial physicochemical evaluation, in vitro biological and biocompatibility testing, and in vivo safety and efficacy assessment in animal models. NCL has conducted preclinical assessment of various classes of nanomaterials including polymers, dendrimers, nanoemulsions, liposomes, colloidal particles, fullerenes, quantum dots, and core-shell nanostructures. Some of these concepts have advanced to clinics and others are in advanced preclinical development.This presentation will cover the NCL’s preclinical characterization resources and collaborative opportunities available to researchers for advancing their concepts to clinic. Data pertaining to the structure-activity relationship studies on nanomaterials and trends in biocompatibility will also be presented.Acknowledgments:Funded by NCI Contract N01-CO-12400 and HHSN261200800001E.
3:30 PM - QQ11.4
Mineralized Tumor Models to Evaluate the Role of Hydroxyapatite in Breast Cancer Bone Metastasis.
Siddharth Pathi 1 , Debra Lin 2 , Lara Estroff 2 , Claudia Fischbach 1
1 Biomedical Engineering, Cornell University, Ithaca, New York, United States, 2 Materials Science and Engineering, Cornell University, Ithaca, New York, United States
Show AbstractBreast cancer frequently metastasizes to bone, where it leads to secondary tumor growth, osteolytic bone degradation and overall poor clinical prognosis. Increasing evidence suggests that microenvironmental cues play a key role in mediating osteolytic metastasis, but little is known about how material properties of the bone mineral matrix influence the underlying processes. The bone mineral matrix represents a composite structure of collagen fibers reinforced with nano-crystals of hydroxyapatite (HA). Current data indicate that the physicochemical properties of HA (e.g., crystallinity, size, and aspect ratio) vary as a function of bone age, location, and disease state. However, the proliferative and osteolytic response of breast cancer cells to these properties remains unclear due in part to the lack of appropriate culture systems. We have developed a mineralized 3-D tumor model that is based on porous poly(lactide-co-glycolide) scaffolds and HA nanoparticles of defined physicochemical characteristics. Subsequently, we have utilized this culture system to study molecular and cellular signaling events inherent to breast cancer bone metastasis. Nanocrystalline HA was synthesized through a precipitation reaction of calcium and phosphate salts, followed by hydrothermal aging. Particle size was controlled via aging time and temperature, and TEM and XRD were used to verify monodispersity and apatite-structure, respectively. Mineralized scaffolds were fabricated by combining PLG and hydrothermally aged HA and processing them through a gas foaming-particulate leaching technique. Osteopontin (OPN), a calcium-binding protein and a known marker of breast cancer metastasis to bone, was preferentially adsorbed onto mineralized scaffolds with smaller and less crystalline HA nanoparticles. Also in these scaffolds, growth of MDA-MB231 breast cancer cells was enhanced. Tumor cell secretion of interleukin-8 (IL-8), a molecule that has been implicated in metastasis-mediated osteolysis, was increased on scaffolds with large HA crystals. This finding is pathologically relevant, as we have additionally found that HA-regulated secretions of IL-8 induce differentiation and activation of osteoclast progenitor cells leading to increased osteolysis. Overall, our studies suggest that the nanoscale material properties of the bone mineral HA represent a key regulator of osteolytic metastasis and that hydrothermally synthesized HA can be incorporated into scaffold systems to create mineralized tumor models for the effective study of breast cancer biology.
4:30 PM - **QQ11.6
Electron Microscopy Investigations of Nanoparticles and Their Applications to Cancer Detection.
Ai Leen Koh 1 2 , Paul Kempen 2 , Robert Sinclair 2
1 Department of Materials, Imperial College London, London United Kingdom, 2 Materials Science and Engineering Department, Stanford University, Stanford, California, United States
Show AbstractIn recent years, researchers have started to explore the use of nanotechnology for early cancer detection. One way of achieving this will be to functionalize nanoparticles with antibodies that specifically bind to target analytes such as biomarkers on cancer cells. Using bio-sensing and detection platforms that recognize changes in sensor signals, (the presence of) the target analytes can be quantified via nanoparticle-biomarker conjugation. Accurate signal quantification not only relies on sensor design; the quality of the nanoparticles themselves is also paramount, as is the degree and specificity of binding.In this presentation, we will discuss the structural characterization of Synthetic Anti-ferromagnetic (SAF) magnetic nanoparticles, Composite Organic-Inorganic surface enhanced Raman scattering (SERS) nanoparticles (COINs) and gold-silica core-shell SERS nanoparticles (Nanoplex TM biotags) for in-vitro cancer diagnostic applications. We will focus on the development and application of electron microscopy-based techniques to characterize the nanomaterial-biology interactions, to assess how, or indeed whether, nanoparticles are attaching to the cancer cells. We successfully determined the binding of CD54-functionalized COINs on the apex of U937 leukemia cell lines using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning Auger microscopy techniques. TEM was used to locate intra-cellularly labeled COINs and to trace the phospho-stat6 signaling pathway in U937 leukemia cells, demonstrating that COINs can be used to detect intracellular phosphorylation signaling events. Nanoplex TM Biotags were conjugated to T-cells by coating the nanoparticles with anionic PEG chains and treating the T-cells with lipofectamine, a common transfection reagent to induce uptake of the nanoparticles. The anionic coating is designed to increase cell uptake of the nanoparticles while the lipofectamine alters the cell membrane to allow the nanoparticles to pass through it. The conjugation between these nanoparticles and the T-cells were then studied using SEM and TEM.In summary, our experiments demonstrate the importance of electron microscopy for analyzing the material-biology interface, for validating the attachment of nanoparticles on and in cells, and for its ability to provide complementary imaging and spectroscopic information to current bio-detection technologies. This research is supported by the Center for Cancer Nanotechnology Excellence Focused on Therapy Response (CCNE-TR) grant (NIH U54). Use of the facilities at the Stanford Nanocharacterization Laboratory and the National Center for Electron Microscopy, Lawrence Berkeley Lab, which is supported by the U.S. Department of Energy under Contract # DE-AC02-05CH11231, is acknowledged.
5:00 PM - QQ11.7
Quantitative Characterization of Competitive Molecular Conjugation on Functional Nanoparticles Using Attenuated Total Reflection Infrared Spectroscopy.
De-Hao Tsai 1 , Melissa Davila-Morris 1 , Frank DelRio 1 , Michael Zachariah 2 3 , Vincent Hackley 1
1 Ceramics Division, NIST, Gaithersburg, Maryland, United States, 2 Process Measurement Division, NIST, Gaithersburg, Maryland, United States, 3 Department of Mechanical Engineering and Chemistry, University of Maryland, College Park, Maryland, United States
Show AbstractIn this study we employed a modified Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy method to conduct surface-sensitive quantitative studies of molecular conjugation on gold nanoparticles (Au-NPs) for applications in nanomedicine. Thiolated polyethylene glycol (SH-PEG) was chosen as the representative ligand because of its ubiquitous use in therapeutic vectors. Adsorption isotherms for SH-PEG as a function of three different relative molecular mass values (1 kDa, 5 kDa, and 20 kDa) were characterized by ATR-FTIR. Using the Langmuir model, the equilibrium binding constants and the relative surface coverage for SH-PEG can be derived under relevant fluid conditions. Electrospray differential mobility analysis (ES-DMA) was employed as an orthogonal comparison, and both the relative surface coverage and equilibrium binding constants show good agreement between ES-DMA and ATR-FTIR. Sensitivity to detection of molecular surface coverage can be as small as 0.01 /nm2 for both ES-DMA and ATR-FTIR. Competitive adsorption of bovine serum albumin (BSA) on SH-PEG-conjugated Au-NPs was also studied. From changes in BSA adsorption and SH-PEG desorption, the displacement of SH-PEG by BSA on the surface of Au-NPs can be quantified. This ATR-FTIR method is demonstrated as a prototype approach to quantitatively study the stability of conjugated SH-PEG in the presence of proteins and other ligands.
5:15 PM - QQ11.8
Electron Microscopy of Raman Active Gold Core Nanoparticles Conjugated to Biological Material for use in Cancer Research.
Paul Kempen 1 , Avnesh Thakor 2 3 , Cristina Zavaleta 2 3 , Bryan Smith 2 3 , Sanjiv Gambhir 2 3 , Robert Sinclair 1
1 Materials Engineering and Science, Stanford University, Stanford, California, United States, 2 Molecular Imaging Program, Stanford University, Stanford, California, United States, 3 Radiology and Bioengineering, Stanford University, Stanford, California, United States
Show AbstractRaman active gold core nanoparticles (R-AuNPs) are a novel surface-enhanced Raman scattering (SERS) nanoparticle, with a 60 nm diameter gold core and 30 nm thick silica shell. The close proximity of an organic Raman layer adsorbed onto the gold core results in a surface enhancement effect that can increase the signal strength by a factor of 1014. In addition to the improved signal strength, the silica shell provides a surface that is both biologically inert and can be readily functionalized to create a targeted nanoparticle. These features make the R-AuNPs ideal for use in early cancer detection and diagnosis. Electron microscopy characterization of R-AuNPs conjugated to biological material is essential to understand how the nanoparticles interact with a biological system. These interactions include how the nanoparticles travel through the body, which organs and cells will uptake the nanoparticles, will the nanoparticles cluster, and is the use of a targeting motif successful. In this work, both scanning and transmission electron microscopy were utilized to study the interaction of R-AuNPs in a number of biological systems.Scanning electron microscopy (SEM) was utilized to study the effectiveness of an antibody targeting motif on the R-AuNPs. R-AuNPs were functionalized with biotinylated monoclonal antibody C11E9 which targets N-acetylmuramidase, a surface protein on Listeria bacteria. SEM samples were prepared by dehydrating and critical point drying the bacteria on a poly-lysine coated cover slip. The samples were then imaged using a backscattered electron detector in the SEM. Backscattered electron (BSE) images taken at 20 kV clearly show the presence of R-AuNPs on the surface of these bacteria. Due to the high atomic number of Au relative to the elements that comprise biological material, the R-AuNPs appear as bright spots against a darker background in BSE images. Secondary electron images confirm that the R-AuNPs are located on the surface of the bacteria.Scanning transmission electron microscopy (STEM) was used to study which organs will uptake the R-AuNPs. R-AuNPs were intravenously injected into mice through the tail vein at a dose of 9.6x1010 nanoparticles. At 5 mins, 2 hrs, 24 hrs, 1 wk, and 2 wks; mice were sacrificed and the liver was fixed, stained, and dehydrated. 150 nm sections were cut using an ultramicrotome and placed on 200 mesh bare copper grids for STEM analysis. For each sample 12150 µm3 of tissue were analyzed. Over time the concentration of R-AuNPs decreased, from 0.047 R-AuNPs/µm3 at 5 minutes to 0.014 R-AuNPs/µm3 at 2 weeks, a 3.4 fold decrease in concentration. In addition, it was found that the R-AuNPs were predominantly located inside vesicles in the tissue usually in clusters. These clusters varied widely in size and number at all time points. These results show that electron microscopy is a powerful tool for gaining insight into the interactions of R-AuNPs with biological systems.
QQ12: Poster Session: Nanotoxicity, Biofouling, and Surface Modification for Biomedical Applications
Session Chairs
Rashid Bashir
Wenbin Lin
Larry Nagahara
Robert Sinclair
Thomas Thundat
Friday AM, December 03, 2010
Exhibition Hall D (Hynes)
9:00 PM - QQ12.1
Surface Modification of Metals and Oxides with Phosphonate Coupling Molecules for Biomedical Applications.
Danielle Laurencin 1 , Hubert Mutin 1 , Julien Amalric 1 , Lenaic Lartigue 1 , Joulia Larionova 1 , Yannick Guari 1 , Gilles Guerrero 1
1 Chimie Moléculaire et Organisation du Solide, Institut Charles Gerhardt Montpellier UMR5253, Montpellier France
Show AbstractPhosphonate coupling molecules (phosphonic acids, diethyl esters and bistrimethylsilyl esters) are good candidates for the grafting of organic groups to the surface of most inorganic biomaterials [1]. In previous work, it was shown that they can form dense, chemically stable monolayers strongly bound to the surface through P-O-M bridges.Here, we wish to give examples of surface modification with phosphonate coupling molecules for biomedical applications: antibacterial coatings for orthopedic or dental implants[2] and water-soluble Fe3O4 nanoparticles functionalized with rhamnose for magnetic resonance imaging[3]. The adhesion of bacteria to surfaces and the subsequent development of bacterial biofilms is the cause of a wide variety of chronic and device-related infections. In order to prevent bacterial adhesion and biofilm formation we developed two phosphonate based nanocoatings able to release different bactericidal species :- silver ion Ag+, which has a broad-spectrum bactericidal activity and a very low toxicity toward mammalian cells. -nitric oxide (NO), a free radical endogenously produced in mammals which is bactericidal and also active in the dispersion of established bacterial biofilms. Magnetic nanoparticles have applications as contrast agents for magnetic resonance imaging or for magnetic hyperthermia. Surface modification of the nanoparticles by hydrophilic biocompatible molecules is needed to increase the circulation time of the nanoparticles, their dispersion and their biocompatibility. In addition, the binding of targeting ligands (such as antibodies, folic acid, peptides, or sugars) to the surface of the nanoparticles is used to improve their targeting ability toward the site of interest. Here we proposed to bind rhamnose (a monosaccharide known for targeting human skin cells) to Fe3O4 nanoparticles (4 nm), using a bistrimethylsilyl phosphonate anchor. This approach allowed us to obtain water-soluble monodispersed rhamnose-coated Fe3O4 nanoparticles presenting superparamagnetic behavior and nuclear relaxivities comparable to Endorem, which are promising for magnetic resonance imaging.[1] Mutin, P. H.; Guerrero, G.; Vioux, A. J. Mater. Chem. 2005, 15, 3761 - 3768. [2] Amalric, J.; Mutin, P. H.; Guerrero, G.; Ponche, A.; Sotto, A.; Lavigne, J.-P. Journal of Materials Chemistry 2009, 19, 141-149.[3] Lartigue, L.; Oumzil, K.; Guari, Y.; Larionova, J.; Guerin, C.; Montero, J.-L.; Barragan-Montero, V.; Sangregorio, C.; Caneschi, A.; Innocenti, C.; Kalaivani, T.; Arosio, P.; Lascialfari, A. Organic Letters 2009, 11, 2992-2995.
9:00 PM - QQ12.10
Controlling Surface Functionality on the Microscopic and Nanoscopic scale: Synthesis of Monomers used for Self Assembled Monolayers & Their Biological Applications.
Matthew Hynes 1 , Joshua Maurer 1
1 Department of Chemistry & Center for Materials Innovations, Washington University in St. Louis, St. Louis, Missouri, United States
Show AbstractSelf-assembled monolayers (SAMs) are a method for functionalizing surfaces in a well-defined and controlled manner. SAMs have been used to provide microscopic and nanoscopic control of reactive functional groups on a substrate. One of the best characterized systems is alkane thiols on gold, which have been used for a wide variety of biological and materials applications. To develop new strategies to generate complex patterned substrates, we have prepared novel monomers with three distinct components; a thiol head group, a long alkane chain, and a glycol tail. The head group allows for covalent attachment to gold-coated substrates and the alkane chain allows for self-assembly through Van der Waals interactions. The tail group contains a tetraethylene glycol moiety, which has been shown to resist nonspecific protein binding. A fraction of the glycol tails within our monolayers have been modified with a photoprotected carboxylic acid to provide a handle for further functionalization. We have explored a variety of carboxylate photoprotecting groups, which have sufficient absorption at 325 nm to be removed by a He-Cd laser. These groups include derivatives of the nitrobenzyl, coumarin, and phacyl protecting groups. After selective deprotection, our surfaces have a free carboxylic acid, which can be used for protein coupling via standard peptide coupling strategies. This technique for patterning proteins is more versatile than the traditional method, microcontact printing, for numerous reasons. First, photodeprotection allows for multiple rounds of protein attachment through successive deprotection and coupling reactions as opposed to microcontact printing, which only allows for a single protein to be patterned. Second, utilizing the cage carboxylic acid groups combined with photopatterning increases the resolution through site selective deprotection. Lastly, this technique provides the ability to produce protein gradients using grey scale lithography.
9:00 PM - QQ12.12
Surface Modification of Nanoparticle by Enzymatically Synthesized Functional Block Copolymer.
Sung-Geun Jung 1 , Young-Rok Kim 1
1 Gradute school of Biotechnology, Kyung Hee University, Yongin Korea (the Republic of)
Show AbstractPolyhydroxyalkanoates (PHAs) have received significant interests from industry and academia because of its biocompatible and biodegradable properties with potential applications in drug delivery and biomedical fields. But it often requires lengthy and complicated steps to attach affinity molecules to the surface of nanoparticles prepared by oil in water (o/w) emulsion method. The ligands on the surface of nanocarrier improve delivery efficiency through specific molecular recognition of the carrier with unique marker molecules in target cells. The surface modification of nanoparticle has been directed mostly by covalent attachment of affinity molecules to its surface but it is depending on the availability of amine or carboxylic acid groups on the surface of nanoparticles.Herein, we demonstrate a new approach to prepare PHA nanoparticles as a drug carrier with tumor targeting ability through simple o/w emulsion method in combination with biological surface functionalization. The surface of PHA nanoparticles was functionalized by the engineered PHA synthase that was coexpressed with a specific ligand through protein engineering. PHA chains grown from the engineered PHA synthase interact with the surface of drug loaded PHA nanoparticle. The hydrophobic interaction between the surface of PHA nanoparticle and growing PHA chain from enzyme stabilized the core-shell structure. The RGD4C moiety that was co-expressed with PHA synthase as a fused form provided the carrier with a targeting capability toward tumor cell. We have characterized hybrid PHB nanoparticles by dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM) and observed size shift of original PHB particles after the surface modification. The diameter of PHB nanoparticles was increased by about 46 nm through the enzymatic surface modification. It means that the enzymatic synthesis of PHB on the PHB nanoparticle contributed to the formation of protein–polymer shell with thickness of 23 nm. We tested the efficiency of the functionalized PHB nanoparticles for tumor targeting by using MDA-MB 231 breast cancer cells in vitro. The fluorescence microscopy revealed that the functionalized PHB nanoparticles are effectively bound to the target cells. This new approach will allow us to design a PHA synthase fused with variety of specific ligands, which would expand its application for the preparation of functionalized nanoparticles.
9:00 PM - QQ12.13
Efficient Surface Modification of Silica Nanoparticles with a Ligand Molecule Having Trimethoxysilyl and Amino Groups.
Hak-Sung Jung 1 , Jin-Kyu Lee 1
1 , Seoul National University, Seoul Korea (the Republic of)
Show Abstract(3-trimethoxysilylpropyl)diethylenetriamine (DETAS) was employed as a surface ligand for the modification of SiO2 nanoparticles, which has multiple amino groups with two secondary and one primary sites, thereby producing a higher number of amine functional groups. The DETAS-modified silica nanoparticles, SiO2-DETAS, were very stable in alcoholic solution and reasonably stable in acidic (pH < 6) aqueous solution without producing insoluble precipitates. The amount of amino functional groups on SiO2-DETAS was quantitatively analyzed by acid-base titration method, and the effective amount of amino functional groups for the next chemical reaction was determined by treating with fluorescent Rhodamine B isothiocyanate (RITC) molecule. The amino surface groups of SiO2-DETAS could also be easily converted to aldehyde groups by treating with excess amount of glutaldehyde (GA), as one of the well-known bioconjugation protocols, and followed to react with biomaterials having amine functional groups such as antibodies. Quantitative analysis results and interesting application based on those bioconjugation reactions from the multiple amino groups on the surface of SiO2-DETAS will be discussed.
9:00 PM - QQ12.14
Self-assembly of Artificial Raft Structures Introduced in Supported Lipid Bilayers on Step-controlled Sapphire Surfaces.
Toshinari Isono 1 , Kenji Yamazaki 1 , Tomoya Wada 1 , Toshio Ogino 1
1 Electrical and Computer Engineering, Yokohama National University, Yokohama Japan
Show Abstract We have studied morphological and chemical control of biointerfaces using single crystalline sapphire surfaces. Because the sapphire surface is atomically flat and chemically inert, it is a suitable material for bio-application. Recently, we found that phase-separation characterized by hydrophilicity and charge potential occurs on step-controlled sapphire surfaces. A lipid bilayer supported on a solid surface is a simple model of cell membranes for in vitro studies. Biological membranes in living cells, on the other hand, consist of several kinds of lipid and protein molecules. In particular, phase-separated microdomain structures (named “raft”) are believed to play an important role in cell membrane functions. In this study, we controlled lateral organization of artificial raft structures introduced in supported lipid bilayers on the step-controlled sapphire surfaces. We used sapphire (0001) surfaces that are covered with bunched steps accompanied with crossing steps and atomically flat terraces. We call this surface a cross-stepped surface. Two domains characterized by hydrophilicity and charge potential different from each other coexist on this surface. Center regions of the terraces (domain A) are relatively hydrophobic and weakly charged and the outer regions (domain B) hydrophilic and negatively charged. Supported lipid bilayers were formed on the step-controlled surfaces by the vesicle fusion method. To form the artificial raft structures, a mixture of phosphocholine (PC), sphingomyelin (SM) and cholesterol was used. The formed lipid bilayers were observed by atomic force microscopy in a buffer solution at room temperature. When electrically neutral PC lipids were used, bilayers and monolayers simultaneously formed on the cross-stepped surfaces: the lipid bilayers selectively formed on the domain B, and the monolayers formed on the domain A. We also prepared a chemically modified surface by an etching using a phosphoric acid. On this surface, the lipid bilayers selectively formed on the domain A because its hydrophilicity is suitable for formation of the lipid bilayers. When charged PC lipids were used, bilayers selectively formed on the oppositely charged region of the etched surfaces. A planar lipid bilayer that is phase-separated in its composition formed on the cross-stepped surfaces using the lipid mixture. The artificial raft structures that exhibit a liquid-ordered phase enriched with SM and cholesterol are assembled on the domain A, and membranes with a liquid-disordered phase enriched with unsaturated PC on the domain B. The lateral interactions between the adjacent lipid molecules are affected by the chemical states and the geometry of the cross-stepped sapphire surfaces. In conclusion, we succeed in formation control of the artificial raft structures incorporated into supported lipid membranes using step-controlled sapphire surfaces.
9:00 PM - QQ12.15
Selective Adsorption of Protein Molecules on Multi-phased Sapphire Surfaces.
Kenji Yamazaki 1 , Toshinari Isono 1 , Tomoya Wada 1 , Toshio Ogino 1
1 , Yokohama National University, Yokohama Japan
Show AbstractBiointerfaces between protein molecules and solid surfaces have attracted much interest because of its importance in the wide range of biomedical and industrial applications. In particular, selective adsorption of protein molecules is an interesting phenomenon because it can be applied to highly sensitive detection of bio-reactions, regenerative medicine and implants. We have tried to control protein adsorption on solid surfaces by designing chemical properties of the substrate surfaces. In this paper, we report on the adsorption behaviors of protein molecules on multi- phased sapphire surfaces toward their selective detection.We used sapphire (0001) surfaces covered with bunched steps accompanied with crossing steps. This surface consists of two domains; the circular domains are relatively hydrophobic and their outer areas hydrophilic. We investigated adsorption characteristics of protein molecules on the multi-phased sapphire surfaces. On these surfaces, ferritin and avidin molecules were examined in a buffer solution. The surface topography was observed by atomic force microscopy (AFM) in the buffer solution at room temperature. Ferritin molecules were preferentially adsorbed on the hydrophobic domains and few molecules on the hydrophilic domains. Avidin molecules were adsorbed on hydrophilic ones, but their non-specific adsorption occurs inside the circular domains. Selection of protein molecules on a solid surface, if possible, is a very promising technique for various biological and medical examinations. We examined selective adsorption of ferritin and avidin molecules when sequentially added to the buffer solution. When avidin molecules were added in the solution after the adsorption of ferritin, they were selectively adsorbed on the hydrophilic domains, avoiding the ferritin-adsorbed hydrophobic domains. When ferritin molecules were added after the adsorption of avidin, non-adsorption of the ferritin molecules was observed even on the circular domains. In this case, the pre-adsorbed avidin molecules hinder the ferritin adsorption. These results suggest that selection of protein species is basically possible if the adsorption sequence is carefully chosen.Next, we report on the detection of protein molecules adsorbed on cross-stepped surfaces using a chemically modified AFM tip. Specific interactions between biomolecules are widely used to detect the target biomolecules. We used the avidin-biotin binding to detect avidin molecules adsorbed on sapphire surfaces. We modified AFM tips with biotin via alkyl chains. Using the biotin-modified cantilevers, we clealy detected non-specific adsorption of avidin molecules on the hydrophobic circular domains.We have shown that selective deposition and detection of protein molecules are possible using carefully designed solid surfaces and biologically modified AFM tips.
9:00 PM - QQ12.16
WITHDRAWN 12/21/10 Electrostatic and Steric Effect of Peptides Functionalized on Self-Asssembled Rosette Nanotubes.
Mounir El Bakkari 1 2 , Rachel Beingessner 1 2 , Jae-Young Cho 2 , Hicham Fenniri 1 2 , Aws Alshamsan 1
1 Chemistry, University of Alberta, Edmonton, Alberta, Canada, 2 , National Institute for Nanotechnology, Edmonton, Alberta, Canada
Show AbstractOur group has reported the synthesis and characterization of rosette nanotubes (RNTs).1a,b These discrete tubular architectures are formed through a self-assembly process under physiological conditions using a self-complementary guanine-cytosine (G^C) hybrid molecule. In solution, the G^C motifs self-organize to form hexameric rosettes which are maintained through hydrogen bonding interactions. The resulting supermacrocycles then π-π stack to form a helical RNT. With this self-assembly approach, the RNTs outer surface can be readily functionalized with a variety of charged or neutral groups, by covalently attaching them to the G^C motif using standard synthetic strategies. This enables the chemical and physical properties of these nanomaterials to be tailored for specific applications. We have already demonstrated for example, that titanium orthopedic implant materials and hydrogel composites which are coated or embedded with short peptide functionalized RNTs, display dramatically enhanced osteoblast adhesion properties.2a,bTo this end, here we expand the scope and the potential of the RNTs by examining the chemical (electrostatics) and physical (sterics) effects of larger charged peptides on the G^C motif self-assembly process. As a proof of principle study, peptides containing up to 15 L-lysine residues were synthesized and covalently attached to the mono (Kn.M) or twin (Kn.T) G^C base using solid-phase synthesis techniques. The self-assembly of these motifs into RNTs in various pH environments were then investigated by scanning electron microscopy (SEM) / scanning tunneling electron microscopy (STEM), transmission electron microscopy (TEM), UV-Vis spectroscopy and circular dichroism (CD).1. a) Fenniri, H.; Mathivanan, P.; Vidale, K. L.; Sherman, D. M.; Hallenga, K.; Wood, K. V. J. Am. Chem. Soc. 2001, 123, 3854. b) Fenniri, H.; Deng, B.–L.; Ribbe, A. E.; Hallenga, K.; Jacob, J.; Thiyagarajan, P. Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 6487. 2. a) Chun, A. L.; Moralez, J, Zhang, L.; Ramsaywack, S.; Fenniri, H.; Webster, T. J. Tissue Eng.: Part A, 2008, 14, 1353. b) Zhang, L.; Rakotondradany, F.; Myles, A. J.; Fenniri, H.; Webster, T. J. Biomaterials, 2009, 30, 1309.
9:00 PM - QQ12.17
Adsorption-Desorption Study of BSA Conjugated Silver Nanoparticles on Collagen Immobilized Substrates.
Chandra Bhan 1 , Almaz Gebregeorgis 1 , Richa Mandlewala 1 , Norman McKoy 1 , Dharmaraj Raghavan 1
1 Department of Chemistry, Howard University, Washington, District of Columbia, United States
Show AbstractThere is a growing interest in the use of protein-nanoparticle conjugates for applications in biomedical, sensing, and advanced imaging. Conjugation of nanoparticles with proteins provides stability and renders additional functionalities for further biological interactions or coupling. At present, there is limited understanding of protein conjugated nanoparticles with other proteins because of the complexities associated with the system. In this study, collagen was chosen as the model protein for investigating the interaction of conjugated nanoparticles with other proteins because collagen provides mechanical support to cells and tissues in addition to performing various other biochemical functions. The adsorption behavior of synthesized BSA conjugated Ag nanoparticles (Ag NPs) on collagen immobilized surface was followed by surface plasmon resonance (SPR) technique by initially studying the formation of collagen layer and subsequent adsorption of Ag NPs to the immobilized layer. As a control experiment, the Ag NPs were introduced onto the 1-octadecanethiol surface without collagen and we noticed much less Ag NPs remained after desorption compared to the collagen substrate. Initial results indicate that nanoparticle adsorption to substrate depends on the chemistry of the underlying substrate. The adsorption on the self assembled monolayer (SAM) was a reversible process, while the adsorption onto the collagen substrate was irreversible. UV-Vis spectroscopy data supported SPR data as there was Ag NPs adsorption from solution onto both collagen immobilized and control substrates. Additionally, a five-fold desorption of Ag NPs from the control substrates was noticed compared to the collagen immobilized substrates. Preliminary atomic absorption spectroscopy results are in agreement with UV-Vis and SPR observations.
9:00 PM - QQ12.18
The Synthesis and Self-assembly Studies of Three Bioactive BMP-7 Short Peptides Modified Rosette Nanotubes for Bone Tissue Engineering.
Alaaeddin Alsbaiee 1 2 , Yupeng Chen 3 , Mounir Bakkari 1 2 , Usha Hemraz 1 2 , Thomas Webster 3 4 , Hicham Fenniri 1 2
1 Chemistry, University of Alberta, Edmonton, Alberta, Canada, 2 , National Institute for Nanotechnology, Edmonton, Alberta, Canada, 3 Chemistry/Devision of Engineering, Brown University, Providence, Rhode Island, United States, 4 Orthopaedic, Brown University, Providence, Rhode Island, United States
Show AbstractBone fractures are one of the most common bone complications. In more severe cases, bone fixation is accomplished using titanium (Ti) implant materials. Unfortunately, the need for revision surgery typically arises due to implant loosening and/or deterioration ofthe implant/bone interface. Rosette nanotubes (RNTs) are a class of self-assembled organic materials possessing biologically-inspired chemistry, dimensions, and nanoarchitecture. RNTs are obtained through the self-assembly of a guanine-cytosine base (G^C motif) that forms a hexameric rosette maintained by 18 hydrogen bonds. The rosettes in-turn stack together to form a 3.5 nm diameter tube that defines a central channel 1.1 nm across. Both the physical and chemical properties of the RNTs can be predefined according to the functional groups that are expressed on their outer surface. This is achieved by simply covalently attaching the desired group onto the G^C motif itself. Bone Morphogenic Proteins-7 (BMP-7) are natural growth factors produced by bone cells that promote the formation and generation of bone and cartilage. BMPs are large proteins, making them too difficult to conjugate with nanostructured materials. However, a recent in-vitro study has shown that three short peptides (a, b and c) chosen from the knuckle region (bioactive area) of BMP-7 result in enhanced osteoblast (bone forming cells) function and adhesion on Ti surfaces (1). This paper presents the synthesis of three functionalized G^C motifs expressing peptides a, b and c, along with their self-assembly studies. 1.(a) Yupeng C.; Webster, T. J. Journal of Biomedical Materials Research, Part A, 2009, 91A(1), 296-304. (b) Chuna, A. L.; Moralez, J. G.; Webster, T. J.; Fenniri, H. Biomaterials 2005, 26, 7304–7309.
9:00 PM - QQ12.19
Bio-conjugation of Gold Nanosphere Dimers.
Bryan Paladini 1 2 , Laura Fabris 1 2
1 Department of Materials Science and Engineering , Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States, 2 Institute for Advanced Materials Devices and Nanotechnology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States
Show AbstractRecent technological advancements have highlighted the applicability of using nanomaterials in the biomedical field to enhance biosensing [1], bioimaging [2], and drug delivery [3]. Systems that combine the optical properties of metallic NPs (i.e. plasmon resonances), with the surface enhancement effects at the NP surface (such as surface enhanced Raman (SER) scattering), along with the possibility of easy functionalization of the NP surface for biological applications, can advance the efficiency in identifying specific medical diseases in addition to providing an improved method for targeted delivery.Such a design is best represented by dimers of spherical gold NPs conjugated to biomolecules, such as proteins. The possibility to introduce multiple functional groups on the NP surface, and to introduce Raman active molecules as SERS reporters at the intermetallic junction, would allow the creation of combined tools for highly resolved imaging, cell targeting and drug delivery. In this contribution, spherical Au NPs were synthesized via the standard Turkevich method of citrate reduction of gold salt [4]. Biphenyl-4,4’-dithiol (DBDT) was chosen in our experiments as the NP linker due to its high Raman cross-section and an ideal length that allows to space the NPs at a distance that favors high SERS enhancement (i.e. ca. 1 nm). DBDT was introduced in the solution to form the dimers exploiting the high affinity of thiols for Au. The dimers were then stabilized and made biocompatible via functionalization with a monolayer of carboxylic polyethylene glycol (PEG-COOH). Human alpha-Thrombin was chosen as the model protein due to its small size (37 kDa) and stability to the experimental conditions, and was conjugated to the NP surface in the presence of EDC and sulfo-NHS. An amide bond can be formed in these conditions between the carboxylic ends of the dimer and the free amine groups naturally present in the protein, and the protein can thus be covalently bound to the NP carrier. An intense SERS signal characteristic of the DBDT located in the intermetallic junction is observable with a Raman microscope. In addition to providing a platform for protein binding, the carboxylic PEG allows the conjugate to be stable in biological buffers. This contribution represents a first step in designing more complex structures that incorporate cellular uptake and drug transportation. Future experiments will include proteins that have selective binding affinities to cellular membranes and targeted delivery to cells will be implemented.1. H. Cho, B. Baker, S. Waschsmann-Hogiu, C. Pagba, T. Laurence, S. Lane, L. Lee, J. Tok Nano Lett. 2008, 8, 12, 4386-43902. J. Kneipp, H. Kneipp, A. Rajadurai, R. Redmond, K. Kneipp J. Raman Spectrosc. 2009, 14, 1-53. A. Dhar, F. Gu, R. Langer, O. Farokhzad, S. Lippard Proc. Nat. Acad. Sci. 2008, 105, 17356-173614. J. Turkevich, P. Stevenson, J. Hillier Discuss. Faraday. Soc. 1951, 11, 55-75
9:00 PM - QQ12.2
Water-soluble Nanocrystals Through Versatile Polymeric Ligands Inspired by Mussel Adhesive Protein.
Daishun Ling 1 , Yong Il Park 1 , Taeghwan Hyeon 1
1 , National Creative Research Initiative Center for Oxide Nanocrystalline Materials and World Class University program of C2E2, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744 Korea (the Republic of)
Show AbstractA mussel inspired hyper-branched polymeric ligand towards surface independent nanocrystals coating was developed in our group. The biomimetic polymeric ligand developed here consists of polyethylene glycol (PEG) grafted hyper-branched cationic polymer and multi-peptide domain. It contains both catechol and primary amine groups, which mimic the structure of Mussel Adhesive Protein (MAP), for chemical binding with various nanocrystals including Fe3O4, MnO, Au, CdSe/ZnS and so on... Furthermore, the advantages of amphiphilic block copolymer ligands’ hydrophobic Van Der Waals interactions and hyper-branched chargeable polymers’ electrostatically driven effect were combined to enhance the physical interactions with the nanocrystals at the same time. This kind of polymeric ligand embodies MAP mimic surface-independent adhesion in nano scale to accomplish universal nanocrystals coating and the physical properties of the nanocrystals are maintained after this ligand coating. The resulting nanocrystals have high stability in aqueous solutions over long time periods, wide pH ranges, salt concentrations and thermal treatments. Also, small molecular drugs and organic fluorescent dyes can be easily incorporated or conjugated with the ligands’ primary amine groups in this system. Our new polymeric ligand coated nanocrystals should play an important role in various nanocrystal-based biomedical applications.
9:00 PM - QQ12.20
Design of Synthetic Vesicles Encompassing End-functionalized Nanotubes.
Michael Nayhouse 1 , Meenakshi Dutt 1 , Olga Kuksenok 1 , Steven Little 1 , Anna Balazs 1
1 Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Show AbstractVia Dissipative Particle Dynamics (DPD) approach, we study the self-assembly of amphiphilic nanotubes into a lipid vesicle, which is immersed in a hydrophilic solvent. Individual lipids are composed of a hydrophilic head group and two hydrophobic tails. Each nanotube encompasses an ABA architecture, with a hydrophobic shaft (B) and two hydrophilic ends (A). To allow controlled transport through the nanotube, we also introduce hydrophilic tethers at one end of the tube. We show that nanotubes initially located in the outer solvent spontaneously penetrate the vesicle's membrane and assume a trans-membrane position, with the hydrophilic tethers extending from the surface of the vesicle. We add nanotubes one at a time after the previous nanotube has been inserted. We characterize the interactions among the nanotubes that have self-assembled into the vesicles’ membrane and focus on their clustering within the membrane. We also show that the nanotubes insertion and clustering within the vesicle strongly affects the vesicle shape in cases of a sufficiently large number of tubes. Ultimately, these nanotube-lipid systems can be used for making hybrid controlled release vehicles.
9:00 PM - QQ12.21
Nanomaterials Library for On-plate Approach Selective Capture of Peptides in MALDI-TOF Proteomics.
Emanuele Barborini 1 , Marta Cristoni 2 , Roberta Carbone 1 , Simone Vinati 1 , Paolo Soffientini 3 , Andrea Di Fonzo 3 , Gabriela Grigorean 3
1 R&D, Tethis, Milan Italy, 2 Department of Physics, University of Milan, Milan Italy, 3 Department of Experimental Oncology, IFOM-IEO Campus, Milan Italy
Show AbstractWithin the effort to find out suitable biomarkers for early diagnosis of oncological malignancies, proteomic approach points on the discovery of relationships between pathologies and proteome. In this scenario, phosphorylated proteins play a key role. Phosphorylation of proteins is in fact a fundamental biochemical process triggered by kinase enzymes, whose action is frequently associated to pathological states. In real clinical cases the identification of phosphorylated proteins is particularly challenging due to the necessity of targeting specific compounds dispersed at low concentration into complex samples.MALDI spectrometry is a powerful analytical technique providing high-sensitivity for detection of low concentration peptides. Before undergoing MALDI analysis, phosphorylated peptides can be separated from complex samples, according to standard enrichment protocols based on TiO2-packed tips, by exploiting phospho-peptide affinity to titanium dioxide. It has been recently demonstrated that phospho-peptide selective capture can be performed with simplified, easier, and shorter protocols directly on MALDI plate, which has been previously functionalized with an oxide coating.Here we report on results of selective capture of phospho-peptides by Ti, Zr, Hf, and Fe nanostructured oxides, deposited on MALDI plates by supersonic cluster beam deposition (SCBD). Chemical state and morphology of the films have been characterized by XPS and AFM, respectively. XPS revealed the expected oxide stoichiometry as well as the absence of contaminants, while AFM showed the same high-roughness surfaces and nanoscale porosity in all investigated oxides.Different concentrations of betacasein tryptic digest were used to evaluate the limit-of-detection of on-plate method, through the signal of the singly phosphorylated 2061 peptide. All nanostructured oxides show a limit-of-detection as low as 100 fmol, similar to that of standard TiO2-packed tips method. Phopho-peptide capture in the case of complex samples has been evaluated either with a mixture of standard proteins (betacasein, fetuin, BSA, ovalbumin, ribonuclease A, cytochrome C), as well as with a real biological sample (Ndc80-Spc25 protein complex). In both cases, selective capture of phospho-peptides was observed.Since SCBD easily allows the production of a wide library of nanostructured oxides, we envisage the possibility to adopt a combinatorial approach in the recognition of functionalized peptides in one single MALDI analysis session. This could be done by processing the same biological sample on an array-like MALDI plate hosting several nanostructured oxides, and exploiting affinity differences between functionalized peptides and different oxides. Array-like MALDI plates could become a novel tool for proteomic base research, as well as for clinical analysis of real, high-complexity samples.
9:00 PM - QQ12.22
In Vitro Behavior and Design of a New Type Implant with Nanostructured Surface.
Julia Mirza Rosca 1 , Doina Raducanu 2 , Maria Aguirre Sanceledonio 3 , David Gonzalez Martin 4 , Agurtzane Martinez Ortigosa 5
1 Mechanical Eng. Dept., Las Palmas de Gran Canaria University, Las Palmas de Gran Canaria Spain, 2 , Politehnica University of Bucharest, Bucharest Romania, 3 Veterinary Faculty, Las Palmas de Gran Canaria University, Las Palmas de Gran Canaria Spain, 4 Mechanical Dept., Technological Institute of Canarias, Las Palmas de Gran Canaria Spain, 5 R&D Dept., Centre of Advanced Surface Engineering (AIN), Pamplona Spain
Show AbstractThis investigation was aimed to investigate the in vitro and in vivo behavior of a Ti6Al7Nb biomaterial with a nanostructured HA-type coating and also the design and realization of a new special knee implant together with a selection of a suitable animal model for preclinical experimentation of the implants.The metallic material used like substrate alloy for layer deposition was a Ti6Al7Nb alloy obtained by double electron beam melting furnace. In order to obtain a nano-crystalline HA-coating first sodium titanate layer was obtained on the surface and then the implant was immersed in Ringer solution with additional PAW1 biovitroceramic (particles under 20 μm). Three different pH Ringer solutions were used (2.5, 7.0 and 9.0) and different deposition times (5, 10 and 19 days) were employed. Microscopy analysis and corrosion tests of the implants relives that the nanostructured HA layer after 19 days of immersion shows promising results as regarding the implant employ in preclinical experiments.After a complex design based on knee bone radiography there has been manufactured two different types of devices for the metallic implants: a metallic plate and a pin. Two plates and two pins were implanted in each animal.For in vivo experiments the chosen animal model was the mini-pig because of its strong chirurgical resistance and perfect anesthesia toleration. For the testing 10 animals were used for implantation and one for the control. When the plate is implanted the bone has to have a good blood supply after the cut in order to avoid bone to die. All experimented implants were maintained in the animal during six months and periodically inspected. No sign of infection or another problem were observed during this period.
9:00 PM - QQ12.23
Increasing Osteoblast Function and Antibacterial Properties Through the Use of Magnetic Nanoparticles.
Harrison Tross 1 , Erik Taylor 1 , Jennie Yoo 1 , Thomas Webster 1
1 Biomedical Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractBone and joint infection (such as osteomyelitis and prosthetic infection) have been reported on an array of implantable devices. Although drugs are available to treat such infection, antibiotics have been ineffective in treating resistant strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa. Magnetic nanoparticles can be directed to a specific target site in the presence of a magnetic field for site-specific drug delivery and an immediate increase in bone density. The goal of this study was to explore the use of superparamagnetic iron oxide nanoparticles (SPION) as a multifunctional platform for the inhibition of bacteria in addition to increasing osteoblast function.In this study, SPION were coated with dimercaptosuccinic acid (DMSA) providing a multifunctional linker which can be used to conjugate short peptides of bone morphogenetic protein-7 (BMP-7) to increase osteoblast function using Sulfo-SMCC chemistry, while simultaneously coating with silver and zinc to improve antibacterial properties. The coated SPION were characterized by vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), Ellman’s reagent (to detect free thiols), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray photo-spectroscopy (XPS). In addition, the nanoparticles were coated with zinc and silver for antibacterial properties and characterized through ICP-AES. Osteoblast cell proliferation was monitored over a five day period in the presence of SPION. Control groups were osteoblasts alone in DMEM. Data was collected on days 1, 3, and 5 and cells were counted and viability determined Bacteria strains of Staphylococcus aureus, Staphylococcus epidermis, and Pseudomonas aeruginosa were inoculated and cultured on agar plates for 12 and 24 hours. The nanoparticles were added to the bacteria cultures and tested for minimum inhibitory concentrations (MIC) at 12 and 24 hours. Crystal violet was used to determine the bacterial biomass. The number of colonies of bacteria was determined using an agar plate count. Results showed significant promise for the use of SPION in anti-infection orthopedic applications. The antibacterial properties and the increased osteoblast proliferating properties of SPION should thus be further studied for device related infections.
9:00 PM - QQ12.24
Osteoblast Responses on Nanocrystalline Diamond Modified by Hydrogen, Oxygen and Ammonia Plasmas.
Lei Yang 1 , Brian Sheldon 1 , Thomas Webster 1 2
1 Engineering, Brown University, Providence, Rhode Island, United States, 2 Dept of Orthopaedics, Brown University, Providence, Rhode Island, United States
Show AbstractDue to its excellent mechanical, tribological and biocompatibility properties, nanocrystalline diamond (NCD) is a promising coating material on metallic implants for improving their efficacy and lifetime. Recent studies have reported enhanced osteoblast (bone forming cell) functions (adhesion, proliferation and diffferentiation) on NCD compared to microcrystalline diamond (both fabricated by chemical vapor deposition). However, even better osteoblast responses on NCD are desirable for establishing strong biological bonding between implant surfaces and host bone tissue, which is critical to ensure orthopedic prosthetic efficacy. Modification of material surfaces is a common approach to promote biological resposens to implant materials, but it has not been widely applied to diamond or nanomaterials. In this work, a feasible surface modification method of NCD using H2, O2 and NH3 gas plasmas was studied. More importantly, osteoblast responses (adhesion/proliferation and differentiation) and adhesive protein (e.g., fibronectin) adsoprtion on the plasma modified NCD were investigated. The results revealed that gas plasma treatment is an effective and simple method to modify NCD for better biological responses. Specifically, the NCD treated by O2 and NH3 plasmas demonstrated significantly improved osteoblast adhesion and long-term functions (alkaline phosphatase activity, calcium deposition and collagen synthesis) than the H2 treated NCD. The results of this study demonstrated the great potential of gas plasma modification towards improving the efficacy of orthopedic implant NCD coatings.
9:00 PM - QQ12.25
Plasma-polymerized Nanoscale PEG-like Coatings for Implanted Electrodes.
Sheryl Kane 1 , Julia Ehrlich 1 , Stuart Cogan 1
1 , EIC Laboratories, Inc., Norwood, Massachusetts, United States
Show AbstractImplanted electrodes have a wide range of clinical applications, from stimulation devices such as pacemakers to recording arrays for control of prosthetics. All of these devices require close proximity to the target cells, either to minimize the voltage needed for stimulation or to maximize recording efficacy. For example, microelectrodes used to record action potentials from neurons in the brain cortex must be within ~100 μm of the firing neuron to detect a signal. As a result, fibrous encapsulation around implanted electrode arrays is one of the primary causes of recording device failure. In addition, electrode impedance tends to increase shortly after implantation due to both fibrotic tissue and electrode fouling by proteins and other biomolecules. Like increased distance between target cells and electrodes, greater impedance increases electrical stimulation voltages and reduces recording ability.The goal of this study is to reduce both electrode fouling and encapsulation by modifying the surface of the device with a thin layer of plasma-polymerized tetraglyme to form a crosslinked network of poly(ethylene glycol) (PEG). PEG is known to resist protein and cell deposition, and it may reduce the thickness of the fibrous scar around the implant. A similar PEG-based coating, poly(ethylene glycol-b-lactic acid) (PEG-PLA), causes less complement activation (a measure of biocompatibility) than common electrode, insulation, and substrate materials. For example, PEG-PLA produced 2.43 ± 0.05 μg of C3a (a complement activation product) per cm2 of material, versus 3.7 ± 1.0 from platinum, 4.0 ± 0.4 from sputtered iridium oxide (SIROF), 4.8 ± 1.0 from polyimide, and 5.0 ± 0.3 from silicon carbide (SiC). In addition, the PEG-PLA coating does not significantly change the charge storage capacity of SIROF penetrating microelectrodes.Unlike other forms of PEG, plasma-polymerized tetraglyme can be covalently bonded to even relatively inert surfaces such as polyethylene and parylene. In addition, the process produces nanoscale (30-250 nm) crosslinked coatings with tunable thickness that conform to the shape of the substrate – a particular advantage for penetrating electrode arrays. To date, five electrode device materials, including two conductors (SIROF and platinum), two insulators (SiC and parylene), and one substrate (polyimide), have been successfully coated with plasma-polymerized tetraglyme. The surface chemistry was confirmed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), with characteristic PEG peaks present at ~1100 (C-O) and 2900 (C-H) cm-1 on all substrates. ATR-FTIR also showed that the coatings on all materials except SiC survived a 24-hour soak test in phosphate buffered saline at 37°C, indicating covalent bonding to the substrates. The PEG-like coating is being applied to penetrating and planar SIROF microarrays to assess the effects of the coating on complement activation and electrochemical performance.
9:00 PM - QQ12.26
Interation of Pseudomonas Aeruginosa Bacteria with Micro- and Nano-diamond Surfaces.
Olga Medina 1 , Jose Nocua 1 , Ramon Gomez 1 3 , Angel De La Cruz 1 3 , Daniel Montano 1 , Frank Mendoza 1 , Mariela Rivera 1 , Javier Avalos 1 2 , Concepcion Rodriguez 1 3 , Gerardo Morell 1
1 Physics, University of Puerto Rio, Rio Piedras Campus, San Juan, Puerto Rico, United States, 3 Biology, University of Puerto Rio at Bayamón , Bayamón, Puerto Rico, United States, 2 Physics, University of Puerto Rico at Bayamón , Bayamón, Puerto Rico, United States
Show AbstractNanotechnology leads to the synthesis of new types of Nanomaterials, such as nanodiamond, that have great potential to enhance the quality of human life. The medical industry can greatly benefit from coatings designed to reduce the bacterial viability on implants, prosthesis and surgery tools. We studied the survival of Pseudomonas aeruginosa bacteria, a common nosocomial pathogen, on nanodiamond (NCD) and microdiamond (MCD) films grown by chemical vapor deposition technique and its inhibitory capacity are compared with samples such as copper (Cu) and silver (Ag), known bactericides, stainless steel (SS) and polyethylene (PE), widely used in households and hospitals. Results analyzed using SEM and AFM microscopy and from time-quantitative measures obtained through a protocol stamping bacterial indicate that nanodiamond inhibits P. Aeruginosa, similar to Ag and Cu. On the other hand, P. Aeruginosa remains alive on SS, MCD and PE for days. Nanodiamond, besides making excellent hard coatings, is a fully biocompatible material because it is completely made of carbon, the element of life. Hence, biomedical applications and biomedical devices can take advantage of its extraordinary self-sterilizing properties.
9:00 PM - QQ12.27
Drug Release and Bactericidal Action of Antibiotic-loaded Scaffolds in Static Conditions.
Tim Ruckh 1 , Rachael Oldinski 2 , Derek Carroll 1 , James Bryers 2 , Ketul Popat 1
1 School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado, United States, 2 Department of Bioengineering , University of Washington, Seattle, Washington, United States
Show AbstractGOAL: The goal of this project was to develop a biodegradable, antimicrobial tissue scaffold that could deliver antibiotics while providing architecture for tissue regeneration. This study determined the release profile and bactericidal efficacy of rifampicin (RFP) against Gram-positive and Gram-negative bacteria in static-flow conditions.SCAFFOLD FABRICATION: Poly(ε-caprolactone) (PCL) was dissolved in chloroform at 12% w/w and oleic acid (OLA) was dissolved in methanol so that the final concentration of OLA amounted to 3% of the mass of PCL in the electrospinning solution. For antibiotic-loaded scaffolds, RFP was dissolved in the PCL-chloroform solution so that the mass was either 8% or 16% of the final solid mass. SCAFFOLD CHARACTERIZATION: Scaffolds were sputter-coated with 10 nm of gold and examined under a scanning electron microscopy (SEM). Visual inspection verified that scaffold morphology was that of continuous fibers, and quantitative measurements of fiber diameters were taken using the SEM software. Scaffold composition was verified using thermogravimetric analysis (TGA). RFP RELEASE: Scaffolds were incubated in PBS; at hours 1, 4, and 8, and days 1, 4, and 7, PBS aliquots were removed and immediately stored at minus-80oC. Concentration of RFP in each aliquot was determined by subtracting the colorimetric absorbance at 690 nm from 570 nm and calculated against five standards plus one blank sample.STATIC BACTERIAL CHALLENGES: Scaffolds were placed in 3 mL of lysogeny or trypticase soy broth and inoculated with either Pseudomonas aeruginosa (PA) or Staphylococcus epidermidis (SE), respectively. Each hour for 0-6 hours, aliquots of the medium were removed and filtered through a 100nm membrane. Trapped bacteria were then stained with Live/Dead BacLight™ stains and counted microscopically. After 6 hours, scaffolds were fixed in 3% glutaraldehyde and dehydrated in an ethanol wash series. Scaffolds were sputter coated with 7nm of gold and examined under SEM.RESULTS: There were significant differences in mean fiber diameter between 10% RFP and the other two scaffolds. TGA confirmed that the 8% and 16% RFP scaffolds contained the intended amounts of RFP. Release profiles for both RFP scaffolds showed a short burst during the first eight hours followed by a zero-order release period during which the scaffolds released nearly equal percentages of their remaining RFP mass. The cumulative release profile for 20% RFP was greater at each time point, and during the zero-order release phase the 20% scaffolds released RFP at a greater rate than 10% scaffolds. Bacterial growth on RFP-loaded scaffolds was hindered compared to control materials. SEM images showed clear differences between bacterial growth on RFP-free and PCL-RFP scaffolds. Both bacterial species formed dense populations and secreted extracellular polysaccharides (EPS) on the RFP-free scaffolds. PA or SE exhibited minimal colonization on both RFP scaffolds.
9:00 PM - QQ12.28
Gold Nanoparticles Functionalized with Ampicillin Overcomes the Antibiotic Resistance of Pseudomonas aeruginosa and Enterobacter aerogenes to Ampicillin.
Tova Samuels 1 , Maria Scott 2 , Sherine Obare 1
1 Chemistry, Western Michigan University, Kalamazoo, Michigan, United States, 2 Biological Sciences, Western Michigan University, Kalamazoo, Michigan, United States
Show AbstractAntibiotics have long been used to destroy microbial pathogens. However, it is well known that microorganisms can develop resistance to antibiotics over time. For example, some isolates of Pseudomonas aeruginosa and Enterobacter aerogenes are resistant to the antibiotic ampicillin. In fact some strains of P. aeruginosa are pan resistant and virtually untreatable. The rise of multi and pan drug resistant bacteria is a significant concern in both developed and developing nations. Consequently, new and effective methods to control microbial pathogens are in high demand. Metallic silver (Ag) and silver ions (Ag+) have long been recognized to have robust toxicity against a broad range of microorganisms. The antimicrobial effects of Ag nanoparticles (NPs) are also well documented and Ag NPs have been used as antibacterial agents in medical applications as well as in a variety of products. One feature of nanoscale surfaces is that they are excellent scaffolds and have been demonstrated to be viable drug delivery agents. The question that arises is how antibiotic immobilization on NP surfaces influences antimicrobial activity. Previous work by us showed that the immobilization of biomolecules at nanoparticle surfaces significantly influences their activity. Monodisperse citrate-stabilized 5 nm Ag and Au NPs were synthesized by the reduction of silver nitrate or gold chloride, respectively, with sodium borohydride. The nanoparticles were characterized by transmission electron microscopy and surface plasmon resonance. Both Ag and Au NPs prepared following this procedure are stable for several months when stored at 4° C in the dark. The antimicrobial effects of ampicillin-functionalized Au NPs was studied with one clinical strain of Shiga toxin-producing Escherichia coli (STEC) [STEC O157:H7], Vibrio cholera, Staphylococcus epidermidis and the ampicillin resistant Pseudomonas aeruginosa, and Enterobacter aerogenes. In this presentation, we will show a comparative study for the antimicrobial effects of ampicillin functionalized Ag NPs and Au NPs or Ag NPs alone, on clinical isolates of food and water borne pathogens.
9:00 PM - QQ12.29
Enhanced Antibacterial Effect of Zinc Oxide Nanoparticles in the Presence of an Ultrasonic Stimulus.
Justin Seil 1 , Thomas Webster 1
1 , Brown University, Providence, Rhode Island, United States
Show AbstractParticulate zinc oxide (ZnO) is a known antibacterial agent. Studies have shown that reducing the size of ZnO particles to nanoscale dimensions further enhances their antibacterial properties. The mechanism of ZnO antibacterial activity may be the release of zinc ions from the material at the grain boundaries. Ultrasound may enhance the release of zinc ions from particle surfaces by mechanical stimulation. Furthermore, upon mechanical deformation of ZnO, a piezoelectric material, a transient electrical charge across the material is produced. The purpose of the present in vitro study was to investigate the antibacterial properties of ultrasonically stimulated ZnO nanoparticles. Staphylococcus epidermidis bacteria were seeded at a known cell density into 96-well plates and observed for 48 h with a 10 min ultrasonication period at 24 h. Optical density reading data was collected every 12 h, with an additional reading taken immediately after the ultrasonication period. ZnO nanoparticles alone reduced bacteria activity. The high concentration (0.1 g/ml) of ZnO nanoparticles reduced bacteria activity further than low concentrations (0.01 g/ml) of ZnO nanoparticles. After 48 h, the combination of a high concentration of ZnO nanoparticles and sonication reduced bacteria activity greater than exposure to nanoparticles or sonication alone. Developing methods and understanding mechanisms for reducing bacteria activity may help reduce potential infection complications following biomaterial implantation. Though it remains to be seen whether the enhanced antibacterial properties are due to a piezoelectric effect of ZnO, enhanced ion release, the induced kinetic energy of the nanoparticles, or to some other unknown mechanism, this study demonstrates the promising potential of ZnO nanostructures and ultrasound for reducing bacteria activity. Ongoing experiments related to this study investigate more powerful and well-defined doses of ultrasonic stimulation as well as other nanoparticle chemistries. Also, a gram positive bacteria strain, Pseudomonas aeruginosa, is being investigated.
9:00 PM - QQ12.3
The Effect of Surface Nanometre-Scale Morphology on Nanostructured Surfaces Functionalization.
Pasquale Scopelliti 1 2 , Marco Indrieri 2 , Antonio Borgonovo 2 , Gero Bongiorno 1 , Luca Giorgetti 3 , Alessandro Podesta 2 , Paolo Milani 1 2
1 Nanostructured Materials Platform, Fondazione Filarete, Milan Italy, 2 CIMAINA - Interdisciplinary Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan Italy, 3 Experimental Oncology, European Institute of Oncology, Milan Italy
Show AbstractSurface nanoscale morphology profoundly influences cell adhesion, spread, growth and differentiation through mechanisms that are poorly understood [1,2]. Proteins that are immobilized on the nanobiomaterial surface play a fundamental role in these mechanisms, mediating the interaction between the surface and cells and regulating the final cell behaviour through complex signalling pathways. Therefore, the quantitative characterization of how nanoscale surface features determine the amount, structure and distribution of immobilized proteins is necessary for understanding cell-nanostructured surface interaction and for the rational design of protein functionalized nanobiomaterials. The knowledge of the protein immobilization process on nanostructured surfaces is relevant to many biomedical research fields such as tissue regeneration, drug delivery, prosthetics, nanotoxicology, biosensing and therapeutic micro- and nano-devices.Here we introduce novel methods for quantitative high-throughput characterization of protein-surface interaction and we apply them in an integrated experimental strategy, in order to study the immobilization of a panel of proteins on nanostructured titania surfaces [3,4]. Thanks to this new approach, we have quantitatively characterized the role of nanoscale morphology in influencing protein immobilization, highlighting the mechanism that determines how proteins organize on nanostructured surfaces. We show that nanoscale morphology significantly increases the amount of immobilized proteins, causing the formation of protein clusters in correspondence with surface nanometric pores. These results define the role of nanoscale morphology as a biomaterial design parameter to control the amount of immobilized proteins and the structure of the protein layer.These findings are highly significant for many applications where nanostructured surfaces are functionalized with proteins or where nanostructures directly interact with biological systems. They are also relevant for the understanding of cell-nanostructured surface interaction and for the general understanding of the nano-bio interface. The systematic quantification of protein-surface interaction has been made possible by the development of new, high-throughput and quantitative methods, allowing the analysis of protein immobilization onto nanostructured surfaces, and the comparison of up to 1,200 interactions in a single experiment [3,4]. These methods can therefore facilitate the screening of biomaterial libraries against panels of proteins, in the framework of combinatorial approaches, to optimize biomaterial performance.[1] Mitragotri, S. & Lahann, J. Nature Mater. 8, 15-23 (2009)[2] Dalby, M. J. et al. Nature Mater. 6, 997–1003 (2007)[3] Scopelliti P.E. et al. The effect of surface nanometre-scale morphology on protein adsorption. PLoS ONE 5(7): e11862 (2010).[4] Scopelliti P.E et al. Fluorescence Photobleaching Quantification for studying protein immobilization.In preparation
9:00 PM - QQ12.30
Staphylococcus Aureus Activity Inhibition of Iron Oxide Nanoparticles in Solution and in Polyvinyl Alcohol Thin Film.
Nhiem Tran 1 , Aparna Mir 2 , Dhriti Malik 2 , Arvind Sinha 2 , Nayar Suprabha 2 , Thomas Webster 3 4
1 Physics, Brown University, Providence, Rhode Island, United States, 2 Material Science and Technology, National Metallurgical Laboratory, Jamshedpur India, 3 Engineering, Brown University, Providence, Rhode Island, United States, 4 Orthopaedics, Brown University, Providence, Rhode Island, United States
Show AbstractAccording to previous studies, bacterial infections are the third most common cause for implant failure. Among all bacteria, Staphylococcus aureus (S. aureus) is one of the most common human pathogens responsible for many types of infection. This bacterium is responsible not only for local infections, such as wound or postoperative infection, but also for prosthetic infections (such as catheters, endotracheal tubes and other biomaterials). Recent reports showed that the ability of S. aureus to resist antibiotics such as penicillin, methicillin, tetracycline, erythromycin and vancomycin) is increasing constantly. Thus, it is necessary to find an alternative treatment (perhaps without the use of antibiotics) for S. aureus infection that is more directed, localized and difficult for bacteria to formulate a resistance. To find such a novel treatment, this study examined the effects of iron oxide (IO) nanoparticles on S. aureus. IO nanoparticles were synthesized via a novel matrix mediated method using polyvinyl alcohol (PVA). The IO nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS). Further, S. aureus were grown in the presence of three different IO nanoparticle concentrations for 4, 12 and 24 hours. Live/dead assays were performed and the results provided evidence that IO/PVA nanoparticles inhibited S. aureus growth at the highest concentration (3mg/ml) at all time points. Further, using the electrospinning method, thin films of IO/PVA nanofibers were created. The films were characterized by TEM, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR). Mechanical properties of thin film were also investigated and compared to pure PVA electrospun films. Results revealed significant promise for the use of IO/PVA films for various anti-bacterial applications.
9:00 PM - QQ12.31
Decreased Attachment of Epithelial Cells and Bacteria to Lubricin Coated Intraocular Lenses.
George Aninwene 1 , Erik Taylor 2 , Gregory Jay 3 , Thomas Webster 2 4
1 Division of Molecular Pharmacology, Physiology & Biotechnology, Brown University, Providence , Rhode Island, United States, 2 Division of Engineering, Brown University, Providence , Rhode Island, United States, 3 Department of Medicine, Section of Emergency Medicine, Brown University, Providence , Rhode Island, United States, 4 Department of Orthopaedics, Brown University, Providence , Rhode Island, United States
Show AbstractStatement of Purpose:Cataract is the leading cause of blindness in the world (1). There are over 6 million cataract surgeries involving intraocular lenses (IOLs) worldwide (2). However, there are three main issues that threaten the lasting success of these surgeries. First, the encroachment of epithelial cells onto the surface of IOLs can lead to a significant loss of visual acuity (3). Secondly, bacterial infection after cataract surgery is a major post operative complication (4). Third, the accumulation of calcium deposits on IOLs may lead to total lens opacification (2). Lubricin is a glycoprotein found in the synovial fluid that plays a major role in providing lubricating and anti-adhesive properties to synovial fluid (5). The purpose of this in vitro study was to investigate the role that lubricin can play to prevent the encroachment of epithelial cells onto the surface of IOLs and as an effective non-immune opsonification agent for resisting bacteria colonization. Description:Poly (methyl methacrylate) (PMMA) and IOSOFT26 IOL samples were obtained from Vista Optics. IOSOFT26 is a copolymer based on HEMA (2-hydroxyethyl methacrylate) and MMA (methyl methacrylate). Samples were sterilized overnight in 70% EtOH.All samples were soaked in LUB (extracted from Bovine synovial fluid (Pel-Freez))at either 100μg/ml or 200μg/ml for a minimum of 2hrs. Human lens epithelial cells (HLEC) (obtained from ATCC (CRL- 11421) were seeded on LUB treated and untreated samples at a concentration of 1x106. Samples were incubated for 4 days, stained using the Live/Dead fluorescent stain, imaged and counted. Staphylococcus aureus (S. aureus) (obtained from ATCC (25923)) were seeded onto the substrates in DMEM. Some samples were soaked in 100μg/ml or 200μg/ml LUB for 2 hours, other samples were incubated with LUB in the media. The bacteria were allowed to adhere under standard cell conditions for 1hr or 4hrs. Samples were then stained with either crystal violet or the Live/Dead fluorescent stain, and analyzed with a spectrophotometer or a fluorescence microscope, respectively. Results: These trials indicate that LUB reduced the adhesion of both HLECs and S. aureus on both PMMA and Iosoft IOL materials. Additionally, 1hr S. aureus adhesion experiments indicated that coatings with either 100μg/mL or 200μg/mL LUB resulted in a decreased bacterial viability on the surface of the PMMA IOL samples.References:1.N. G. Congdon, D. S. Friedman, T. Lietman, JAMA 290, 2057 (October 15, 2003, 2003).2.L. Werner, Journal of Cataract & Refractive Surgery 33, 713 (2007).3.Y. Hesse, J. Kampmeier, G. K. Lang, A. Baldysiak-Figiel, G. E. Lang, Graefes Archive for Clinical and Experimental Ophthalmology 241, 823 (Oct, 2003).4.L. Kodjikian et al., 2002.5.B. Zappone, M. Ruths, G. W. Greene, G. D. Jay, J. N. Israelachvili, Biophysical Journal 92, 1693 (2007).
9:00 PM - QQ12.32
High Antibacterial Activity of ZnO Micro-structures Prepared via Solution Process.
Rizwan Wahab 1 , Amrita Mishra 2 , Soon-Il Yun 2 , Young-Soon Kim 1 , Minwu Song 1 , Donggyu Kim 1 , Hyung-Shik Shin 1
1 Chemical Engineering, Chonbuk National University, Jeonju, Chollabukto, Korea (the Republic of), 2 Food Science and Technology, Chonbuk National University, Jeonju, Chollabukto, Korea (the Republic of)
Show AbstractThe microbial infection/contamination in human beings is very common and some time it causes serious illness and other health hazards. With the emergence and increase of micro organisms resistant to multiple antibiotics and the continuing emphasis on health care costs, many researchers have tried to develop new, effective antimicrobial reagents free of resistance and cost. Towards this direction, in this paper we presents the high anti bacterial activity of ZnO micro-structures prepared via solution process against four pathogenic bacteria S.aureus, E.coli, S.typhimurium and K.pneumoniae. The observation of antibacterial activity was analyzed at different concentration of zinc oxide micro-structures (5µg/ml-45µg/ml) using nutrient broth medium in 24 hours incubation period. Our investigation reveals that at lowest concentration of micro-structures solution inhibits the growth of microbial strain, which was found to be 5µg/ml for S.aureus, S.typhimurium and K. pneumoniae whereas for E.coli, it was calculated to be 15µg/ml. The morphology of ZnO micro-structures with bacteria was also analyzed via Bio-TEM images. The diameter of each micro-structures lie between 2-3µm as observed from FE SEM and Transmission electron microscopy. The composition of synthesized material was analyzed by FTIR spectroscopy and on the basis of morphological and chemical characterization, a possible mechanism is proposed for the interaction of pathogenic strains to zinc oxide micro-structures.
9:00 PM - QQ12.33
Assessing the Toxicological Properties of Nanostructured Hydroxyapatite Clusters Embedded in Polymer Nanofibrous Mats Seeded with Osteoblasts.
Perena Gouma 1
1 Material Science and Engineering, SUNY Stony Brook, Stony Brook, New York, United States
Show AbstractThis work is a novel approach to nanotoxicology and it studies how biomaterials’ properties of polymer hybrids shape their interactions with living cells. It focuses on assessing the toxicological properties of osteinductive biomaterials, in particular nanostructured Hydroxyapatite (HA). Nanostructured bioceramics belong to a class of important functional inorganic materials used in health applications and cosmetic products. Human bone is composed of nano-assembled collagen type1 and hydroxyapatite [1]. So HA has been widely studied in bone tissue engineering as bioactive and biocompatible inorganic materials. Many studies have shown that organic and inorganic composite scaffolds support attachment, differentiation and proliferation of osteoblasts. The hybrids of bioceramics with polymers comprise the new generation of biosensors, filtration devices, etc., and thus it is important to understand how they behave when interfacing with living cells and organisms. This study uses materials science expertise to fully characterize the structural and chemical changes that biomaterials experience upon interactions with the cells and their environment.
9:00 PM - QQ12.34
The Effect of Zinc Oxide Nanoparticles on Different Types of Human Skin Cells under Ultraviolet Light Exposure.
Chienhsiu Lin 1 , Simon Marcia 2 , Wilson Lee 3 , Miriam Rafailovich 1
1 Material Science & Engineering, SUNY at Stony Brook, Stony Brook, New York, United States, 2 Oral Biology & Pathology, SUNY at Stony Brook, Stony Brook, New York, United States, 3 , Estee Lauder Corp, Melville, New York, United States
Show AbstractWe have investigated the effects on zinc oxide (ZnO) and titanium dioxide particles on different types of human skin tissue cells; dermal fibroblasts, keratinocytes, and adipocytes. We found that in general damage was greater to the fibroblast cells than to the keratinocytes, or adipocytes. We also experimented with coating the particles with charged polymers, which are able to absorb the electron emitted. Minimal damage to cells was observed even at high concentrations of the coated particles. Damage was enhanced with exposure to UV light, except when the coated particles were used. In this case, minimal damage occurred even after exposure, indicating that these particles were able to impart good protection against UV light , without risk of additional toxicity to cells.
9:00 PM - QQ12.35
Size Dependent Particle Toxicity in Drosophila.
Deborah Gorth 1 , Thomas Webster 1
1 Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractThe most exciting characteristic of nanotechnology is that by changing just the characteristic size of a material you can also change the substance's reactivity. Nanotechnology has harnessed this fact to create more effective medical treatments, but the influence of size on toxicity has not been thoroughly addressed. This study examines the influence of size on alumina, silica and silver toxicity in drosophila by exposing eggs to particle concentrations ranging from 10 ppm-10,000 ppm and quantifying their effect on development. Alumina shows minimal toxicity, even at 1,000 ppm there is not a drastic difference between the control and treatments with either conventional sized or nanoscale particles. Silica treatments cause a discernable effect on the eggs ability to develop into adults. Particles above 100 nm cause about a significant drop in the number of flies that can develop into adults while nanoscale silica causes only small reduction in the eggs' developmental success. Nanoscale silver has a more robust toxicological effect than silica or alumina. At 100ppm silver particles 100 nm and larger in diameter cause complete lethality while the 20-30nm particles allow for adult flies. Overall this study shows that size has an effect on particle toxicity, and particles under 100 nm are less toxic than those larger than 100 nm.
9:00 PM - QQ12.4
Functionalized Clay Nanomaterials for Wound Healing Applications.
Christopher Vaiana 1 2 , Lawrence Drummy 2 , Richard Vaia 2 , Athanasios Bubulya 3 , Rajesh Naik 2 , Madhavi Kadakia 1
1 Biochemistry and Molecular Biology, Wright State University, Dayton, Ohio, United States, 2 Materials & Manufacturing Directorate, Air Force Research Laboratory, WPAFB, Ohio, United States, 3 Biological Sciences, Wright State University, Dayton, Ohio, United States
Show AbstractImproved wound healing is an area of constant research, especially for in-theater military applications. Wound healing is a complex multi-staged process, making it difficult to treat with any single material. This problem may be addressed with the use of hybrid materials that can play multifunctional roles in the wound healing process. Silicates have been previously shown to augment the natural blood clotting response. In this study, biofunctionalized aluminosilicates are studied in vitro for wound healing applications. Our initial studies focused on adsorption of Horseradish Peroxidase (HRP) onto montmorillonite (MMT) nanosheets which served as a model to examine the biological activity retained in the protein-silicate complexes. Upon optimization of the adsorption protocol for HRP, we next used a similar approach to form Epidermal Growth Factor (EGF) – MMT complexes The binding of EGF to MMT was confirmed using biochemical and materials characterization techniques. Subsequently we tested the effects of MMT-EGF on cell motility and proliferation in human epidermal cell lines in vitro. Cell growth, movement, and protein expression of epidermal cells post-treatment with EGF-MMT were assayed, and a pro-growth response was observed. This study serves as a basic demonstration of the applied use of biologically active protein-clay nanocomplexes, the principles of which can be applied to numerous areas of research.
9:00 PM - QQ12.6
Geometrically Tunable and Surface-modification Switchable Water Adhesion and Flow Resistance of Superhydrophobic Silicon Nanotip/rod.
Hsieh- Cheng Han 1 , Hung-Chun Lo 2 , Ching-Chun Chang 3 , Yu-Kuei Hsu 1 , Cheong-Wei Chong 4 , Kuei-Hsien Chen 1 3 , Li-Chyong Chen 1
1 , Center for Condensed Matter Science, National Taiwan University, Taipei Taiwan, 2 , Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu Taiwan, 3 , Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei Taiwan, 4 , Department of Physics, National Taiwan University, Taipei Taiwan
Show AbstractIn the present work, the effects of surface modifications on the superhydrophilic nanostructure arrays with water contact angle (WCA) close to 2o are investigated. Two different geometries of the silicon nanostructures are studied, including nanotips and nanorods, which are produced by self-masked electron-cyclotron-resonance plasma enhanced process [1]. The as prepared nanotips, typically with an apex of 2 nm, are hydrophilic; and in general their hydrophilicity increases with increasing heights. Upon modification with FAS117 self assembled monolayer, the hydrophilic properties of the as-prepared nanotips can be changed to hydrophobic, with a remarkable change in the WCA from 2o to >160o. Moreover, these nanostructures can be switched to superhydrophobic if their surface is fluorinated and their hydrophobicity also increases with increasing heights. For the nanorods with the apex ranging from 100 nm to 550 nm, similar trend with the nanotips is observed. Meanwhile, the superhydrophobic nanotips (WCA>160o) show ultra-low flow resistance of water with the sliding angle lower than 1o, measured with 1 ul water droplet. In addition, the critical weight of the water droplet on the nanorods (WCA>160o) is over 15 mg, as the substrate tilted at 90o. These results show the weakest or strongest adhesion between the water and the silicon nanotips / nanorods, which has never been demonstrated in the literatures before.[1] Y. F. Huang, K. H. Chen, L. C. Chen, et al., Nature Nanotech. 2, 770 (2007).
9:00 PM - QQ12.7
Multivalent Presentation of Proteins on a Stimulus Responsive Micelle.
Wafa Hassouneh 1 , Karl Fischer 2 , Robert Branscheid 2 , Manfred Schmidt 2 , Ashutosh Chilkoti 1
1 Biomedical Engineering, Duke University, Durham, North Carolina, United States, 2 Institute of physical chemistry , Johannes Gutenberg University of Mainz , Mainz Germany
Show AbstractPolymeric micelles have gained immense interest in the biomedical field as drug delivery vehicles. Despite reports of the presentation of small molecules and peptide ligands on the corona of micelles of synthetic polymers and recombinant artificial polypeptides, there have been, to our knowledge, no reports of uniform presentation of an intact protein on the corona of a polymer micelle; the ability to do so would provide a new set of targeting agents for drug delivery and functional imaging in medicine. Herein, we investigate a potential platform for multivalent display of proteins using stimulus-responsive block elastin-like polypeptides (ELPs) to induce temperature triggered self-assembly into micelles that present multiple copies of the protein on their corona. ELPs consist of the pentapeptide repeat [Val-Pro-Gly-Xaa-Gly] where Xaa is a guest residue that can be any amino acid except proline. ELPs undergo a sharp reversible transition from an extended soluble state to a collapsed aggregated state upon heating above a critical temperature known as the lower critical solution temperature (LCST). The LCST for a given ELP composition increases as the hydrophobicity of the guest residues increases. We have previously found that when two ELP blocks with disparate hydrophobicities (and hence disparate LCSTs) are joined to form a block copolymer (ELPhydrophilic -ELPhydrophobic), a micellar state is observed for certain block ratios in a temperature range where the hydrophobic block is collapsed and the hydrophilic is still hydrated. A polymeric architecture of protein-ELPhydrophilic-ELPhydrophobic, which can be easily constructed at the genetic level, would allow for the display of a given fused protein on the corona of the micelle. We aim to understand the rules that govern micelle formation for the protein-ELPhydrophilic-ELPhydrophobic architecture by systematically varying the structural parameters of the temperature triggered self-assembly process. We hypothesize that these structural parameters are the size of the fused protein, the degree of hydrophilicity match between the fused protein and hydrophilic block, and the disparity of hydrophilicity between the two ELP blocks. Initial results using the protein thioredoxin as a model protein show micelle formation for five ELP block copolymer ratios. The micelles were characterized by temperature-programmed turbidimetry, dynamic and static light scattering, and cryo-transmission electron microscopy. The findings indicate formation of monodisperse particles with hydrodynamic radii between 24-31 nm that are spherical in shape and are composed of approximately 50 monomers/particle; together these results suggest micelle formation. These initial results have prompted further studies with a wider set of fused proteins and ELP block compositions and lengths to understand the rule that govern the self-assembly of diblock ELPs that present an entire, intact protein at their hydrophilic terminus.
9:00 PM - QQ12.8
Effects of Size and Surface-conjugated Peptides on Intracellular Uptake of Gold Nanoparticles.
Eunkeu Oh 1 , James Delehanty 2 , Kimihiro Susumu 1 , Kim Sapsford 3 , Hedi Mattoussi 4 , Igor Medintz 2
1 Optical Science, Naval Research Laboratory, Washington, District of Columbia, United States, 2 Center for Biomolecular Science and Engineering, Naval Research Laboratory, Washington, District of Columbia, United States, 3 , US Food and Drug Administration, Washington, District of Columbia, United States, 4 Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, United States
Show AbstractThe use of inorganic nanoprobes (such as Au nanoparticles and luminescent quantum dots) has provided the community with new tools that possess remarkable advantages compared to conventional dyes in biomedical imaging, clinical diagnostics and therapeutics. Gold nanoparticles (AuNPs), in particular, have size and shape-dependent plasmonic absorption, pronounced scattering cross-sections, and photo-induced thermal responses, which make them uniquely suitable for applications such as contrast agents, imaging, diagnostics and photo-thermal therapy. The latter application requires control over the AuNP interactions with live cells, their cytosolic uptake and their ultimate “storage’ inside the cells. These properties and their dependence on the AuNP size and surface functional groups remain poorly understood and not widely explored. Here we show that AuNPs modified with end-functionalized bidentate poly(ethylene glycol) ligands can be covalently and controllably conjugated to cell penetrating peptides. The surface functionalized AuNPs were prepared using a one-step aqueous phase synthesis that we recently developed, with control over their diameter from ~1 to ~100 nm. These AuNP-peptide conjugates were used to test the efficiency of cellular uptake and localization within the intracellular compartments. In particular we tested the effects of varying the size and number of peptides attached to each AuNP. Our findings show that NP to membrane interactions and the eventual destination of the NP depends on the intricate balance between the nanocrystal diameter and the conjugate valence. Smaller AuNPs localized in the nucleus and larger AuNPs resided on the cell membrane. We also demonstrate the minimal cytotoxicity of the AuNPs upon cellular delivery.
9:00 PM - QQ12.9
Synthetic Control over the Structure and Symmetry of Carbon Nanotubes: Towards Biomedical Applications.
Michael Lowry 1 , Alfredo Rayms-Keller 1 , Karen Long 1 , Francisco Santiago 1 , Victor Gehman 1 , Kevin Boulais 1
1 , Naval Surface Warfare Center, Dahlgren, Virginia, United States
Show AbstractCarbon nanotubes (CNTs) are appealing materials for biomedical applications due to their unique chemical, electrical and mechanical properties. CNTs can be conceptualized as cylindrical materials composed of rolled-up sheets of atomically-thick graphite layers (i.e., graphene). In most instances, the properties and behavior of a CNT can be described according to a single symmetry vector (i.e., chiral vector) and the number of concentric layers that are present in the structure. Critical performance traits such as chemical activity and response to an electronic or magnetic impulse depend on the structure and symmetry of the material. The ability to strategically control structure and symmetry of CNTs would enable tunable materials for sensing, delivery and detection and could have a profound influence on the advent of nanotechnology in biomedical research. A method for deliberately controlling the local atomic structure of CNTs has been developed; analysis of these materials is on-going within our group. The methodology, performance and potential impact of this work will be discussed.