Roger Narayan University of North Carolina
Suwan Jayasinghe University College London
Sungho Jin University of California-San Diego
William Mullins Office of Naval Research
Donglu Shi University of Cincinnati
VV1: Functional Materials and Devices
Tuesday PM, December 01, 2009
Room 202 (Hynes)
9:00 AM - VV1.1
Improved Culture Conditions for Measuring T-Lymphocyte Responses for Cell Based Cancer Therapy.
Carole Perry 1 , Graham Hickman 1 , Akhilesh Rai 1 , Balwir Matharoo-Ball 1 , Robert Rees 1 Show Abstract
1 School of Science and Technology, Nottingham Trent University, Nottingham United Kingdom
The interactions between biological systems and biomaterials are of great importance to regenerative medicine. Key to this understanding is assessing how cells react when presented with materials of varying physical and chemical properties. ‘Omics’ technologies such as MALDI mass spectrometry are ideal methods to examine the interactions between cell and surface.To this end we have built upon existing methods for the manufacture of bio-mimetic silica film surfaces with novel chemical and physical properties. Our methods have been able to produce silica surfaces under mild chemical conditions on a range of substrates suitable for use in cell culture applications. These surfaces can be fabricated with characteristics such as wetting properties ranging from hydrophobic to hydrophilic or even super-hydrophilic, depending on the methods used.The initial silica surface produced was trialed as a cell culture surface with a melanoma cell line (FM3) on both a hydrophilic silica surface and conventional cell culture polystyrene. After a period of culturing the culture media and lysed cells were examined using current MALDI based proteomic techniques to generate a peptide mass fingerprint characteristic of the cells cultured on both of the surfaces.Through comparison of the proteomic studies we have determined that the cell culturing surface can have a dramatic effect on the cell proteome. The melanoma line cultured on a hydrophilic silica surface showed a radically altered peptide mass fingerprint as compared with the cells cultured on the traditional cell culture polystyrene surface, both in terms of the proteins expressed into the cell culture media and the proteome of the cell itself. Examination of the morphology of the melanoma cells via optical microscopy showed that while the cells cultured on the different surfaces demonstrated similar morphological characteristics they showed important variations in their expressed proteome.Further investigation with different cells, including different cell surface chemistries in relation to culturing materials with different surface properties should provide great insight into the interactions between biological systems and materials destined for biological applications.
9:15 AM - VV1.2
Cell-Based Detection of Synthetic Pathogens Using Cell Impedance Sensing.
Bhavana Mohanraj 1 , Nate Schiele 1 , Anne Hynes 1 , David Corr 1 , Cerasela Dinu 1 , Douglas Chrisey 1 Show Abstract
1 Materials Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, New York, United States
We demonstrate a new approach to electrically sense pathogens using cells as the receptor-sensing element. Electrical Cell-substrate Impedance Sensing (ECIS) was used to monitor the confluent growth of human dermal fibroblasts and their exposure to an anthrax simulant namely Bacillus cereus. ECIS was conducted at frequencies between 4 – 64 kHz and it was found to be an excellent measure of cell growth, micro-motion, and their overall intracellular and intercellular morphological responses when challenged with various agents. When exposed to the digestive enzyme trypsin we observed an instantaneous and unambiguous change in the capacitance, of approximately 67% at 32 kHz almost instantaneously. When exposed to the anthrax simulant Bacillus cereus spores, we observed no response during germination and a very small response when the bacillus cells thrived in the fibroblast growth media. The ECIS response was consistent with a live-dead assay whereby it was found that no cells had died and no significant morphological change was observed. While Bacillus cereus is in the same genetic family as Bacillus anthracis, its pathological lethality on the cellular level for fibroblasts was negligible. Our work shows that the ECIS measurements were an extremely sensitive measure of fibroblast morphological response. In this presentation, we will challenge prototype biosensors with other biological warfare simulant pathogens such as B. Subtilis or B. Atrophaeus (simulant for smallpox) as well as with against chemical warfare agents dimethyl methyl phosphonate (nerve agent – sarin) and 1,5 dichloropentane (blister agent – mustard gas).
9:30 AM - VV1.3
Implantable BioMEMS for Localized Hyperthermia and Cancer Drug Release.
Yusuf Oni 1 2 , Guoguang Fu 1 2 , Christian Theriault 1 , Alex Van Hoek 1 , Rohith Chandrasekhar 3 , Emily Paetzell 1 2 , Wole Soboyejo 1 2 Show Abstract
1 Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, United States, 2 Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey, United States, 3 Electrical Engineering, Cooper Union, New York, New York, United States
This paper presents a novel implantable bio-micro-electro-mechanical system (Bio-MEMS) device for the localized treatment of cancer. The device uses a combination of heating (hyperthermia) and drug release to kill breast cancer cells. Cancer drug release is controlled by the use of modified poly(N-iso-propyl-acrylamide) (PNIPA) hydrogels with hydrophobic/hydrophilic copolymers and interpenetrating network structures. The gels are encapsulated in biocompatible poly-di-methyl-siloxane (PDMS) with micro-fluidic channels that convey the drug (paxlitaxel) to cancer cells/tissue. The thermo-sensitive properties (swelling) and fluid/drug release characteristics of the gels are elucidated along with the effects of localized heating with micro-wires. A synergistic killing of breast cancer cells is shown to occur as a result of the combined effects of localized cancer drug release and hyperthermia.
9:45 AM - VV1.4
Micro and Nanopatterning Tools to Produce Biomimetic Chips Based on Molecularly Imprinted Polymers.
Cedric Ayela 1 , Helene Lalo 2 , Samuel Guillon 2 , Thierry Leichle 4 , Fanny Vandevelde 3 , Ana Valvanuz Linares 3 , Liviu Nicu 2 , Karsten Haupt 3 Show Abstract
1 , Laboratoire de l'Intégration du Matériau au Système UMR 5218; University of Bordeaux, Talence France, 2 , LAAS-CNRS; University of Toulouse; 7, avenue du Colonel Roche F-31077, toulouse France, 4 , Institute of Physics, Academia Sinica, Taipei 115, Taipei Taiwan, 3 , Univeristé de Technologie de Compiègne, CNRS UMR 6022, Compiègne France
Micro and nanobiochips are of interest in biomedical applications like diagnostic, molecular screening and drug discovery. Recent advances in this field allow introducing technologies to create highly sensitive patterns. Classically, biochips are arrays of natural biomolecules locally immobilized on a surface. However, short life-time and poor stability of natural molecules when used out of their native conditions promotes introduction of alternative sensitive layers, particularly biomimetic polymers. Molecularly imprinted polymers (MIPs) represent a novel area of polymers capable of molecular recognition with the same affinity and selectivity as their natural counterparts. Their synthetic composition offers enhanced long-term stability compared to natural biomolecules. One other advantage of the polymeric matrix, characteristic of MIPs, is their powerful combination with micro and nanotechnologies to create biochips.Here, we present recent approaches developed in our groups to pattern MIPs at micro and nanoscale. First, Micropatterning tools were developed and referenced as contact and non-contact techniques. Contact method is based on array of silicon cantilevers fabricated by micromachining techniques and mounted on a three-stage automated spotter. This resulted in arrays of MIPs serially and precisely localized on a substrate, with resolution down to 20µm. Alternatively, a parallel approach was initiated by taking benefit of photopolymerization of MIPs to create patterns by photolithography. After spin-coating prepolymers, reticulation was initiated using a mask and resulting MIPs were in a wide variety of features with a resolution down to 1.5µm. By repeating sequentially deposition and local polymerization, a multi-array approach was also introduced. Final objective using these techniques is to compare performances of resulting MIPs in terms of sensitivity, integration, mass production and versatility.More recently, evolution of nanotechnologies made possible to engineer nanostructures. Main issues concern high throughput screening and testing with enhanced sensitivity by increasing the surface area of the MIP material. In this field, soft lithography and nanowires approaches are of major interest since they allow producing nanopatterns with high aspect ratio. Both methods succeeded to create MIPs nanofeatures. Nanofilaments were produced with elevated density, resulting in a factor 40 increase of the surface area compared to a flat surface. These conditions favored accessibility to binding sites and in molecular recognition assays, sensitive levels of detection were reached. A similar behavior was also observed when MIPs were patterned by soft lithography. Features were formed as a network of nanolines of 500nm wide and 400µm long with a pitch of 1µm, covering a large area of 400x400µm2. Thanks to developed techniques, we will conclude on perspectives on MIPs micro and nanopatterns as efficient alternatives to create advanced biochips.
10:00 AM - **VV1.5
Bioinspired Inorganic/polymer Thin Films.
G. Hirata 1 , S. Diaz 2 , P. Chen 2 , M. Meyers 2 , Joanna McKittrick 1 Show Abstract
1 Mechanical and Aerospace Engineering Department, University of California, San Diego, La Jolla, California, United States, 2 , Center for Nanoscience and Nanotechnology-UNAM, Ensenada Mexico
Studies of hard biological materials such as marine shells, animal teeth, horns and bones have produced fascinating ideas for mimicking their micro/nanostructure in the lab. In this work we have analyzed the morphology ad mechanical properties of the nacreous portions of red abalone shells by SEM, TEM, XRD and the chemical compositions by EDS and ESCA. Bioinspired laminates were fabricated as multi-layers of several biocompatible materials: CaCO3 (aragonite)/polymer, ZrN/polymer and ZrO2/polymer for various polymer compositions, by using a combination of dc magnetron sputtering and pulsed laser deposition on glass, quartz and silicon substrates. Substrate temperatures for film deposition were varied in the range of 25-115°C. The films are composed of nanocrystalline or amorphous particles with different degrees of porosity as observed by TEM and AFM. High resolution TEM analysis at the inorganic/organic interface revealed well formed inorganic films which are separated by the polymeric layer (10-50 nm). The hardness values showed an increase for the inorganic film/polymer stacked system as compared with the single film. A more detailed analysis of the results together with AFM/nanoindentation measurements will be presented. This research is supported by ARO Grant W911F-08-1-0461 and NSF Grant DMR 0510138.
10:30 AM - VV1.6
Bio-electrospray Validation from Cells to Organism.
Suwan Jayasinghe 1 Show Abstract
1 Mechanical Engineering, University College London, London United Kingdom
Tissue engineering is a field of interdisciplinary sciences being extensively researched as it is a promising and possible solution for organ transplantation. Various biomaterials and cell-seeding techniques have been developed to construct 3-D tissue in the laboratory. However, many problems of seeding cells in 3-D scaffolds pose several challengers. Thus there are numerous approaches invented with regards to handling cells directly. Our technique, bio-electrospray (BES), has been developed to be able to manipulate cells and materials simultaneously. The method was proved that it is feasible to directly jet cells at high concentration without affecting cell viability. Moreover, in this study, cell functions were investigated and presented to assure the possibility of using BES as a strategy for tissue engineering. Hence stem cells (MSC), primary cells (blood) and whole organism (C. elegans) were used to assess their associated biologics post treatment. The metabolic assay result of electrosprayed MSC have shown the same propagation efficiency along 3 days as controls. Cell viabilities, apoptosis by key enzyme assays during 24 hours after jetting and necrosis by PI staining, subsequent FACS scan after jetting, were also investigated. No significant numbers of cell deaths were investigated. Additionally, gene expressions by RT-qPCR on whole blood cells were observed by 13 specific primers to both specific and constitutive genes. Genetic level was reported as delta Ct for 78 cross comparisons. No differences of gene expression among sprayed and non-sprayed samples were observed. Finally the embryo of C. elegans were treated and examined for productivity, heat shocked response and global gene expressions. Brood size experiments have confirmed the egg laying capacity of electrosprayed samples are as efficient as the control, no GFP activation of heat shock responses as well as no significant differences in gene expressions have identified. These experiments have confirmed that BES is capable of directly handling cells for tissue engineering without perturbing viability, proliferation and gene expression. We are currently running tissue creation by using BES to position cells for controllable cell patterning for possible organ construction.
10:45 AM - VV1.7
Nano- and Micro-Scale Adhesion in Drug-eluting Stents.
Ting Tan 1 , Juan Meng 1 , Nima Rahbar 2 , Hannah Li 3 , George Papandreou 3 , Cynthia Maryanoff 4 , Winston Soboyejo 1 Show Abstract
1 , Princeton University, Princeton, New Jersey, United States, 2 , University of Massachusetts Dartmouth, North Dartmouth, Massachusetts, United States, 3 , Cordis Corporation, Warren, New Jersey, United States, 4 , Cordis Corporation, Spring House, Pennsylvania, United States
This paper presents the results of a combined experimental and theoretical/computational study of nano- and micron-scale adhesion and interfacial fracture in drug-eluting stents (DES). We have previously published the development of an atomic force microscopy (AFM) method to quantify the adhesion forces between and cohesive forces within the layers of a drug-eluting stent (DES). Surface pairs representing both the individual components and the complete chemistry of each layer within the DES were prepared, and measurements of the pull-off forces between coated AFM tips and substrates were obtained to evaluate all possible interactions occurring in the DES structures. As a model, the CYPHER® Sirolimus-eluting Coronary Stent was studied. A combination of adhesion theory and fracture mechanics concepts was then used to obtain estimates of the mode I fracture toughness values. The experimental measurements of the mode mixity dependence of interfacial fracture toughness were shown to be consistent with crack-tip shielding estimates from zone/row fracture mechanics models.
11:00 AM - VV1.8
Localized and Sustained Release from Drug-Loaded Implantable Devices.
Dattatri Nagesha 1 , Evin Gultepe 1 , Robert Cormack 2 , Mike Makrigiorgos 2 , Srinivas Sridhar 1 Show Abstract
1 Physics, Northeastern University, Boston, Massachusetts, United States, 2 Radiation Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, United States
There are a number of biomedical implants that are used today that are capable of localized drug delivery for improved therapy, enhanced tissue adhesion, decreased immune response and biocompatibility. Non-erodible surfaces especially nanoporous alumina and titania have been used for improved drug loading and release capabilities. However, there is a poor understanding on the elution kinetics of drugs from within these nanoporous surfaces. To study this, nanoporous alumina templates with precise control on pore size, distribution and height was fabricated by anodization method. Templates were loaded with fluorescent Doxorubicin (Dox) as the model drug molecule and release of Dox was monitored using in-situ fluorometry. After an initial burst release phase during the first 100 minutes, which follows non-Fickian diffusion, a long time sustained release followed for several weeks. Constructing a model for sustained release kinetics show that activated surface densities dependent desorption was in effect for nanoporous templates. In localized drug delivery from drug-loaded implants from within tumor sites there is lack of theoretical modeling to predict drug distribution and diffusion upon release. This was studied using drug-loaded polymer coatings on gold fiducial markers. Currently, these markers are used to increase spatial accuracy in delivering radiation treatment for cancer therapy. Elution of drugs locally from these fiducials from within the tumor can further enhance their role as a treatment modality. Results from the modeling study of drug diffusion and in vitro drug release experiments from these fiducials will be discussed in this presentation. This work was supported by IGERT Nanomedicine Science and Technology Program (NSF 0504331), Dana Farber Cancer Institute and Northeastern University
11:15 AM - VV1.9
Effect of Processing Conditions on the Microstructure and Sirolimus Elution from Poly (lactide-co-glycolide) Films.
Andrew Ro 1 , Robert Falotico 1 , Vipul Dave 1 Show Abstract
1 Therapeutics and Advanced Research, Cordis Corporation, Johnson and Johnson, Warren, New Jersey, United States
Supercritical carbon dioxide is a viable solvent to process drug-containing polymer devices for drug delivery. It can also be used to modify the morphological features of both polymer and drug at mild temperatures, which presents a prospect to tune drug release and degradation of the device. Poly (L-lactide-co-glycolide) (PLLGA) and poly (DL-lactide-co-glycolide) (PDLGA) films containing sirolimus were prepared using a solution-casting method. Various combinations of processing parameters (e.g. temperature and pressure) were used during supercritical CO2 extraction in order to remove residual solvent and to obtain various polymer and drug morphologies. The morphological features of polymer and drug were characterized by x-ray scattering and differential scanning calorimetry. A range of polymer and drug crystallinities were obtained and the resultant morphologies were dependent on supercritical CO2 extraction conditions and the stereochemistry of the polymer. Heat of fusion values for the polymers ranged from 0 to 40 J/g and the values correlated with the stereoregularity of PLGA. The drug phase in the PLGA films exhibited heat of fusion values ranging from 7 to 46 J/g and was dependent on the chemistry of the PLGA matrix and processing conditions. Surface features of the sirolimus-containing films were analyzed using electron microscopy. Depending on the physical properties of the polymer and drug, the sirolimus-containing PLGA films exhibited unique drug release profiles and in vitro degradation behavior. Crystallinity and stereochemistry of the PLGA matrix were significant determining factors for drug diffusion kinetics.
11:30 AM - VV1.10
Unique Mechanical Properties from Melt Processing Polylactide.
Jianbin Zhang 1 , SuPing Lyu 1 , Lian Luo 1 , Byrant Pudil 1 , Jim Schley 1 , Mike Benz 1 , Adam Buckalew 1 , Kim Chaffin 1 , Chris Hobot 1 , Randy Sparer 1 Show Abstract
1 Medtronic Strategy and Innovation, Medtronic, Minneapolis, Minnesota, United States
Poly(lactide) (PLA) and its copolymers can degrade thro