Yuhei Hayamizu, Tokyo Institute of Technology
Hendrik Heinz, University of Akron
Carole Perry, Nottingham Trent University
Candan Tamerler, University of Kansas
GG2: Nanomaterials with Biomolecules I
Tuesday PM, April 07, 2015
Park Central Hotel, 2nd Floor, Metropolitan III
2:30 AM - *GG2.02
The Chemical Nature of the Gold Nanoparticle-Biomolecule Interface
Catherine Jones Murphy 1
1University of Illinois at Urbana-Champaign Urbana United StatesShow Abstract
Gold nanoparticles are being explored for in vivo applications, including imaging, drug delivery and therapeutic agents. It is now well-known that upon immersion in biological fluids, nanoparticles will be immediately overcoated by a "corona" of proteins, ions, and other species present in biological fluids. Understanding the basic thermodynamics, kinetics, conformation and orientation of bound biomolecules to nanoparticle surfaces is a critical piece of the larger picture of "what the cell sees." Using chemical tools, in this tallk I will discuss how to measure these processes, and how the nature of the surface has impact all the way to the level of cells and organisms.
3:00 AM - GG2.03
Gold Nanoparticle - Lipid Self-Assembly and Interactions: Insights from Computer Modeling
Zilu Wang 1 Elena Dormidontova 1
1University of Connecticut Storrs United StatesShow Abstract
There has been a surge of interest in applications of gold nanoparticles in biomedicine for imaging and therapeutic purposes in recent years. Thus understanding the behavior of gold particles inside polymeric or lipid carriers as well as the interaction of gold nanoparticles with lipid bilayers is highly desirable. While experimentally one can estimate the degree of encapsulation and stability of aggregates containing gold nanoparticles, the molecular details of interactions between nanocarrier and gold nanoparticles remains obscure. Computer modeling can provide valuable insights in this area. Using coarse-grained molecular dynamics simulations with a Martini force-field we investigate the interactions between hydrophobically-modified gold nanoparticles and a mixed lipid bilayer, nanodisk or vesicle. To obtain a lipid nanodisk a combination of at least two lipids with short and long tails is required. We investigate the equilibrium structure of self-assembled lipid with encapsulated single of multiple gold nanoparticles as well as probe the dynamic pathway for gold nanoparticle encapsulation. The effect of lipid composition (i.e. fraction of short to long lipids), gold nanoparticle size and length of hydrophobic tethers attached to gold nanoparticle will be discussed. Furthermore we will also discuss the interaction between encapsulated gold nanoparticles, which in some cases results in gold clustering. Cholesterol is one of the natural components of cell surface, thus it is of importance also to address the role of cholesterol in the behavior of self-assembled lipid structures and cholesterol-gold nanoparticle interactions. We will discuss and compare the behavior of gold nanoparticle containing lipid aggregates with and without cholesterol. The results of computer modeling will be compared with available experimental data and predictions will be made regarding the influence of the intrinsic properties of lipid aggregates and gold nanoparticle on the outcomes lipid/gold nanoparticle co-assembly and gold nanoparticles clustering inside the lipid aggregates.
3:15 AM - GG2.04
A Robust Surface Plasmon Resonance Based Protocol to Study Biomolecules-Nanoparticle Interactions
Abhijeet Patra 2 1 Ding Tao 3 Gokce Engudar 4 Chester Drum 3 Thirumalai Venkatesan 2 James Kah 4
1NUS Graduate School for Integrative Sciences amp; Engineering Singapore Singapore2NUSNNI Nanocore, National University of Singapore Singapore Singapore3Cardiovascular Research Institute, National University of Singapore Singapore Singapore4National University of Singapore Singapore SingaporeShow Abstract
The interaction of biomolecules (proteins, lipids et al) with synthetic nanoparticles topic of great interest in the allied fields of drug delivery, theranostics and bionanotechnology in general. The formation of the protein corona on any NP injected into the blood stream has been known for a while now, but methodologies to study the phenomenon are constantly being invented and reinvented, simply because there is no best method yet. This is a hurdle in the way of truly understanding the implications and adoption thereby, of nanomedicine.
Herein we demonstrate a robust protocol based on the Biorad XPR36 surface plasmon resonance setup to study affinities of serum proteins towards nanoparticles. We employ a hetero-bifunctional linker to immobilize our model nanoparticles (Au NPs) onto the surface of the chip. A layer of alginate matrix on the native gold surface of the chip keeps non-specific binding to a minimum. Thereafter, conditions were optimized for obtaining very stable immobilized AuNPs on the chip surface. Consequently, it became possible to study interactions between the proteins of interest, human serum albumin (HSA), fibrinogen, immunoglobulin G and apolipoprotein and the AuNPs. Through the use of this method, we could obtain kinetic data for these protein-NP complex formation interactions.
We also used the same method to demonstrate the significant retardation of corona formation on AuNPs functionalized with polyethyleneglycol (PEG) moieties.
With the identification of a suitable linker, the protocol can be used to study the interaction of any native or surface-functionalised NP with biomolecules. This can reveal important details as to what would be the final identity of a NP in the context of the physiological system. Instead of getting snapshots in time of the “state” of a NP incubated with serum proteins, this method lets the seeker have real time data - a possibility to visualize the formation of corona as and when it happens.
3:30 AM - GG2.05
Monitoring the Size and the Stability of Zinc Oxide Quantum Dots in Biological Media: A Soft Ionization Mass Spectrometry Technique (MALDI-TOF-MS)
Jean Jacques Gaumet 1 Gabriel Gaiffe 1 Stephane Dalmasso 1 Pierre Magri 1 Raphael Schneider 2
1University of Lorraine Metz France2University of Lorraine Nancy FranceShow Abstract
With the development of material sciences, the characterization of nanomaterials has become a critical issue in managing their fascinating size-dependent physical and chemical properties. Controlling these properties from the synthesis to the application phase, and consequently to their fate as a worldwide environmental and societal concern is becoming more and more imperative. The potential toxicity of nanoparticles needs to be evaluated when developing applications in a responsible way. Zinc oxide ZnO nanoparticles can be found largely as powders and dispersions with antibacterial, anti-corrosive, antifungal and UV filtering properties. ZnO nanoparticles can also be used for various applications ranging from food and cosmetics up to coatings agent and in the manufacturing of concrete. Research is actively being conducted towards in solar cells, photocatalysis, optical devices and sensors which have already started to show economic potential worldwide.
The principal techniques currently used to achieve the characterization of nanoparticles are physical and physico-chemical methods, such as Transmission Electron Microscopy (TEM), X-ray diffraction, and optical spectroscopies. All these analytical tools are excellent for global analyses of clusters and nanomaterials. Soft ionization mass spectrometry (MS) methods such as Matrix Assisted Laser Desorption Ionization coupled with Time of Flight MS (MALDI-TOFMS) have already proven their potential as tools in the nanometrology of small-sized II-VI quantum dots (QDs) such as CdS, CdSe, ZnS and ZnSe. Mass spectra of these nanocrystals are consistent with TEM and optical spectroscopy measurements [1-2].
In this paper, we present a joint physical/physico-chemical study and, more specifically, the first application of MALDI-TOF-MS to analyze small-sized ZnO QDs (3-3.5 nm diameter range) synthesized by sol-gel chemistry and stabilized through an aminosilane coating. The organic shell increases the QDs stability and dispersibility in aqueous solution. The ligands were first quantified by thermogravimetric analysis (TGA), then a careful investigation of the stability of ZnO QDs was initiated once these QDs were dispersed in different media (water, biological buffer,hellip;) for a period up to 6 weeks. Positive ion mode mass spectra showed a decrease in mass and consequently in diameter during aging, which can be ascribed to the degradation of ZnO QDs.
In conclusion, the unique combination of MALDI-TOF-MS and physico-chemical techniques brings new insights concerning the structure analysis, the stability and consequently the potential toxicity of ZnO QDs. This new strategy in nanometrology will be extended to other II-VI materials in the near future.
 A. Aboulaich, D. Billaud, M. Abyan, L. Balan, J.J. Gaumet, G. Medjahdi, J. Ghanbaja, R. Schneider ACS Appl. Mater. Interfaces, 4 (5) 2561-2569 (2012).
 M. Fregnaux, J.J. Gaumet, S. Dalmasso, J.P. Laurenti, R. Schneider Microelectron. Eng.108, 187-191 (2013).
4:15 AM - GG2.06
When Less is More: Grafting Density and Colocation Affect Cell Internalization of Peptide Decorated Nanoparticles
Nevena Todorova 1 Ciro Chiappini 2 Morgan Mager 2 Benjamin Simona 2 Imran I. Patel 2 Molly M. Stevens 2 Irene Yarovsky 1
1RMIT University Melbourne Australia2Imperial College London London United KingdomShow Abstract
Nanoparticle functionalization with peptides has proven to be a good strategy to inhibit particle aggregation, increase nanoparticle solubility and develop nanocarriers and biosensors [1,2]. Cell-penetrating peptides, such as, the transcription transactivation TAT peptide from human HIV-1 virus, have become a popular choice for transfection and other types of cellular delivery . Studies have shown that TAT-peptide functionalized gold nanoparticles (AuNP) have the ability to penetrate cell membranes and localise in the nucleus [4,5], making them potentially a good system for drug-delivery applications, albeit with variable performance.
Detailed investigation of the effects of peptide concentration and distribution in the functionallayer at all-atom resolution can aid the design of gold nanomaterials for efficient drug delivery. With this in mind, we have performed an experimental and computational study on the effects of TAT peptide concentration on the structure and dynamics of the peptide layer on the 3 nm AuNP surface and its impact on the NP's membrane permeation capacity .
We show that cell internalisation of TAT functionalised nanoparticles is strongly dependent on TAT surface concentration and distribution. We present the mechanism by which TAT may become inactive upon surface immobilisation and demonstrate how the local environment of the functional peptide grafted onto the nanoparticle surface may affect properties essential for efficient cellular uptake. We found that a notably increased membrane activity correlates with the peptide backbone rigidity and increased basic residue solvent exposure attained at a particular concentration range of the functional peptides. The theoretically predicted membrane permeating capacity was confirmed experimentally while we also revealed molecular properties relevant to the experimentally observed inactivation with increasing TAT concentration. Our results suggest that nanoparticles may be engineered to specifically permeate membranes by targeted conjugation of peptides at specific concentration and surface distribution.
 P.D. Howes, R. Chandrawati, M.M. Stevens “Colloidal nanoparticles as advanced biological sensors” Science 346:1247390 (2014)
 A. Makarucha, N. Todorova, I. Yarovsky “Nanomaterials in biological environment: a review of computer modelling studies” Eur. Biophys. J, 40:103 (2011)
 N.A. Brooks, et al. “Cell-penetrating peptides: Application in vaccine delivery”, Biochem. Biophys. Acta, 1805:25 (2010)
 Z. Krpetic, et al. “Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.” ACS Nano 5:5201 (2011)
 J.M de la Fuente, C.C. Berry “Tat peptide as an efficient molecule to translocate gold nanoparticles into the cell nucleus”, Bioconjugate Chem. 16:1176 (2005)
 N. Todorova, et al. “Surface presentation of functional peptides in solution determines cell internalization efficiency of TAT conjugated nanoparticles” Nano Lett. 14(9):5229 (2014)
4:30 AM - *GG2.07
Genetic Design of Biology/2D Atomic-Layer Solid Interfaces
Mehmet Sarikaya 1
1University of Washington Seattle United StatesShow Abstract
Genetically Engineered Peptides for Inorganic solids (GEPI) are of a broad interest due to their capability in biofunctionalization of solids and utility as molecular linkers, erector sets and assemblers as well as tiny enzymes to synthesize inorganics under biologically viable conditions. Further refining combinatorial mutagenesis approaches, e.g., cell surface and phage display libraries, originally adapted from the principles of drug design, our laboratory has been experimentally selecting 1000s of GEPIs for a variety of noble metals (Au, Pt, Au, Ti), oxides (SiO2, ZnO, Al2O3, ZrO2), semiconductors (GaN), and minerals (HAp, quartz, calcite, aragonite, magnetite, diamond, sapphire, and graphite). To accelerate directed evolution processes, our Center also established bioinformatics methods to de novo design multifunctional chimeric constructs as second, third and higher generation peptides. Despite their short sequences (<25AAs) and, hence, intrinsically disordered structures in water, the versatility of GEPIs stem from their predictable folding conformations specific to a given surface with known physico-chemical characteristics. With the advent of 2D single atomic layer solids, we have recently developed rational approaches to design functional bio/nano interfaces via point and domain mutations. Based on the understanding of the fundamental surface phenomena, e.g., diffusion, assembly, and surface organization, these novel approaches allow us to intermolecular forces to construct peptide-enabled hybrid nanostructures with single atomic layer solids (graphene, MoS2, WeSe2, BN) allowing addressable chemical or physical functions. We will discuss latest developments in designing solid-binding peptides with specific surface recognition and assembly characteristics augmented by computational modeling (MD, MM, QM, kMC, etc.) and, finally, present examples in implementations in molecular-technology and -medicine, e.g., surface resistance spectroscopy, graphene-FET cancer biosensors, and nanophotonic devices. Funded by USA-ARO, NSF-DMR BioMat & MRSEC, NIH-NIDCR & NCI, JAPAN JST PRESTO.
5:00 AM - GG2.08
Interfacial Design of Nanostructured Silicon Photonic Materials for Biomedical Applications
Tiffany Huang 1 Kristopher Kilian 1
1University of Illinois at Urbana-Champaign Urbana United StatesShow Abstract
Porous silicon (PSi) is a promising multifunctional biomaterial due to its large surface area for drug loading, tunable optics for biosensing, inherent biocompatibility and tailored biodegradation through control of surface chemistry. However, the promise of multifunctionality has been limited due to difficulties in chemical passivation for controlled degradation and relatively low sensitivity for biosensing in aqueous environments. Previously we showed how control over surface chemistry can significantly extend the lifetime of PSi materials, thus allowing the real-time monitoring of secretion from adherent cells in culture. In this presentation I will show how chemically modified mesoporous silicon photonic crystals can be used as “smart” substrates for monitoring cellular processes. First, I will show how loading the nanopores of PSi films with pharmacological compounds can be used for sustained release to guide the differentiation of mesenchymal stem cells to the bone cell lineage. Next, I will present a strategy to pattern gold islands in diverse geometric configurations across a PSi photonic crystal for use of orthogonal surface chemistries that differentially control the fate of adherent neural stem cells in culture. Finally, I will present the integration of a hydrogel defect layer into the photonic architecture as a means to detect secreted protease enzymes from adherent cells. Across all of these examples, careful control of the interface chemistry is critical to enabling the multifunctionality of nanostructured PSi materials for next generation implantable photonic devices and biomaterials for regenerative medicine.
5:15 AM - GG2.09
A Nanohybrid System Based on Holotransferrin and Maghemite Nanoparticles as a Promising Theranostic Device
Miryana Hemadi 1 Helene Piraux 1 Jun Hai 1 Souad Ammar 1 Florent Barbault 1 Florence Gazeau 2 Philippe Verbeke 3 Jean-Michel El Hage Chahine 1
1Universiteacute; Paris Diderot Paris France2Universiteacute; Paris Diderot Paris France3Universiteacute; Paris Diderot Paris FranceShow Abstract
Magnetic Nanoparticles are extensively used in theranostics: hyperthermia, enhancement of contrast in MRI, etc. The main problem with nanoparticles is their delivery to the target cells . To this purpose, the overexpression of transferrin-receptor 1 in cancer cells makes transferrin a potential vehicle for nanoparticles . Transferrin solubilizes Fe3+ in sera and when iron-loaded, it is recognized by receptor-1, which is anchored in the plasma membrane . This Triggers the receptor-mediated endocytosis of the two proteins [4,5]. We develop here a "Trojan horse" system based on this endocytosis of the holotransferrine-receptor adduct to intracellular delivery of maghemite nanoparticles. Different sizes of maghemite (Fe2O3) superparamagnetic nanoparticles (5, 10 and 15 nm) were synthesized, coated with 3-aminopropyltriethoxysilane (APTES) and coupled to holotransferrin (TFe2) by amide bonds. Each nanoparticle (NP) carried a known number of holotransferrins (TFe2-NP). This transferrin construct was tested in vitro and remains active after grafting and interacts with its receptor rapidly (50 µs) with an overall dissociation constant (11 nM) . HeLa cells were incubated for several time intervals with rhodamine-labeled TFe2-NP and NPs. Confocal fluorescence microscopy showed that NPs do not cross the plasma membrane within 1 hour, whereas the constructs holotransferrine-maghemite are internalized in the cytosol in endosomes in less than 15 minutes (below). Furthermore, preliminary magnetophoresis results showed, in Lymphocyte T cells, that the rate of internalization of NPs grafted onto holotransferrine is three times larger than that of raw NPs in a culture media containing: 0, 10 and 55 % FCS. These very promising results seem to exclude the formation of a protein corona and validate our strategy. This hypothesis was also confirmed by molecular modeling. Thus, this nanohybrid system constitutes an interesting model for theranostic devices able to follow the main iron-acquisition pathway.
 A. Salvati, A.S. Pitek, M.P. Monopoli et al., Nat. Nanotechnol., 8 (2013) 137.
 T.R. Daniels, et al., Biochim. Biophys. Acta, 1820 (2012) 291.
 R.R. Crichton, Iron Metabolism: From Molecular Mechanisms to Clinical Consequences. Third Edition ed. West Sussex: J.Wiley & Sons (2009).
 A. Dautry-Varsat, A. Ciechanover, H.F. Lodish, Proc. Natl. Acad. Sci. USA, 80 (1983) 2258.
 M. Hemadi, P.H. Kahn, G. Miquel, et al., Biochemistry, 43 (2004) 1736.
 H. Piraux, J. Hai, P. Verbeke et al., Biochim. Biophys. Acta., 1830 (2013) 4254.
5:30 AM - GG2.10
Computational Approaches in Molecular Recognition and Surface Dynamics of Peptides on 2D Solids
Sefa Dag 1 Yuhei Hayamizu 2 Mehmet Sarikaya 1 David Starkebaum 1 Tamon Page 1
1University of Washington Seattle United States2Tokyo Institute of Technology Tokyo JapanShow Abstract
Although some peptides are known to bind to carbon-based solids, fundamental phenomena such as substrate specific peptide binding, conformational transformations and surface self-diffusion have not yet been fully understood. In light of the recent experimental observations of combinatorially-selected engineered solid-binding peptides that assemble to form long range ordered molecular nanostructures on atomically flat surfaces, e.g., graphite and MoS2, here we present a comprehensive simulation study, supported by experimental observations, on the structural and dynamic characteristics of engineered peptides using classical molecular dynamics (CMD) in aqueous environment. The focus of the current study is to determine adsorption free energy and diffusion dynamics of engineered dodecapeptides, including wild type (GrBP5-WT) and its 8 separate mutations with different anchoring domains and tail sequences. In particular, the specific role of the single residue mutations were studied which stabilize structural motifs of the peptide mutants on graphene and MoS2 through molecular recognition of the surface lattice. Our calculations show that the strength of peptide adsorption on the solid surface can be regulated using even a single amino acid mutation, with levels ranging from no adsorption to moderate or strong binding concomitant with altered surface dynamics. A strong correlation can be developed between the rates of peptide self-diffusion on the solid vs their adsorption strength and molecular footprint that develops on the surface upon refolding. The specific role of self-diffusion is correlated with possible mechanism of self-assembly that result in long-range ordered biomolecular nanostructures on single layer materials which also include WSe2 and BN. Research supported by the NSF-MRSEC Program, DMR #0520567 and USA-DOE&’s Resources of NERSC via ERCAP with the Project ID. GrBP5, and NIDCR Fellowship Program.
Tuesday AM, April 07, 2015
Park Central Hotel, 2nd Floor, Metropolitan III
9:30 AM - GG1.01
Bio-Directed Assembly of Functional One-Dimensional ZnO Nanostructures
Chung Hee Moon 1 Tam-Triet Ngo-Duc 1 Marzieh Tousi 2 Elaine D Haberer 1 3
1University of California, Riverside Riverside United States2University of California, Riverside Riverside United States3University of California, Riverside Riverside United StatesShow Abstract
Zinc oxide (ZnO) is a direct wide band gap semiconductor material (3.37 eV) useful for many electronic and optoelectronic applications including sensors, light emitting diodes, and photocatalytic devices. Bio-directed synthesis of ZnO is a promising technique for morphological control of nanostructures at benign temperature and pressure conditions. Specifically, ZnO synthesis utilizing free or unbound peptides in solution, as well as peptides chemically bound to planar substrates has been reported. Such peptides were able to initiate ZnO crystal growth and influence the relative growth rate of specific crystallographic planes, however they lacked the long range order needed for hierarchical assembly. In this work, one-dimensional (1-D) ZnO nanostructures were assembled using a M13 bacteriophage template that displayed a high copy number of well-ordered ZnO-binding peptides along its length. This ZnO-binding filamentous virus, which was approximately 6 nm in diameter and 880 nm in length, had a protein capsid primarily composed of thousands of a-helical major coat proteins, pVIII, arranged in a highly ordered five-fold symmetry. A ZnO-binding peptide was genetically displayed on each of these pVIII coat proteins creating a high aspect ratio scaffold with numerous densely-packed, highly-organized binding sites to aid in morphological control. The peptide fusion was discovered with combinatorial phage display using a pVIII library to ensure that its length, size, and chemical nature were compatible with the tightly packed nature of the pVIII major coat protein. The identified 8-mer ZnO-binding sequence was shorter in length and less positively charged than previously reported peptides with affinity for ZnO. Moreover, M13 bacteriophage that displayed this peptide on the pVIII protein coat were able to bind ZnO at densities nearly 100-fold more than the M13 wild-type virus. Transmission electron microscopy and scanning electron microscopy were used to characterize nanocrystal size, size distribution, morphology, and crystallinity of the assembled 1-D ZnO nanostructures. Furthermore, electron diffraction and energy dispersive x-ray spectroscopy were used for analysis of semiconductor crystal structure and composition. Two-terminal devices were fabricated from the 1-D ZnO nanostructures and photoresponse was measured. This simple synthesis method allows hierarchical assembly of 1-D nanostructures with specificity which can be translated to other materials systems with modification of the biological template.
9:45 AM - GG1.02
Peptide-Based Strategies to Control the Structure/Function Relationship of Nanocatalysts
Marc R. Knecht 1 Ryan Coppage 1 Hadi Ramezani-Dakhel 5 Beverly Briggs 1 Nicholas Bedford 2 Joseph Slocik 3 Anatoly Frenkel 4 Hendrik Heinz 5 Rajesh Naik 3
1University of Miami Coral Gables United States2National Institute of Standards and Technology Boulder United States3Air Force Research Laboratory Dayton United States4Yeshiva University New York United States5University of Akron Akron United StatesShow Abstract
Peptide-based strategies represent new avenues to access functional catalytic structures that operate under biological conditions. The activity of these structures arises from the unique biotic/abiotic interface developed between the peptides and the metallic nanocatalyst. In this regard, we have probed two different classes of biomimetic nanocatalytic materials where the peptide is either directly bound to the particle surface or used as a template to generate large metallic networks. Our results indicate that the localized interactions between the peptide and nanostructure play a key role in controlling the resultant catalytic functionality. These approaches can be applied for the generation of different monometallic materials and has recently been expanded for the fabrication of bimetallic alloys to enhance the catalytic reactivity. Furthermore, these materials can be used as model systems to probe fundamental reaction mechanisms, where our results support a metal leaching-based approach for C-C coupling reactions. By controlling the material morphology, biological interactions, and metallic composition, wide ranging catalytic functionality and potentially selective reactivity could be achieved using biomimetic materials that operate under green conditions.
10:00 AM - GG1.03
Genetically Driven Formation of Biotemplates Made of Tobacco Mosaic Viruses: Towards Nanostructured Bio/inorganic Hybrids
Petia Atanasova 1 Nina Sitz 1 Shawn Sanctis 3 Johannes Maurer 2 Sabine Eiben 4 Holger Jeske 4 Joerg J. Schneider 3 Joachim Bill 1
1Institute for Materials Science, University of Stuttgart Stuttgart Germany2INM - Leibniz-Institute for New Materials, Saarbruecken Saarbruecken Germany3Technical University of Darmstadt Darmstadt Germany4University of Stuttgart Stuttgart GermanyShow Abstract
The evolution-optimized processes of biomineralization yield multifunctional biominerals consisting of bioorganic and inorganic components. The properties of these nanostructured solids are often superior to their inorganic counterparts. Biomineral formation occurs in aqueous solution at ambient conditions and involves biopolymeric templates and interfaces that govern the mineralization of the inorganic components. The generation and the structure of these templates are genetically determined. Accordingly, the genetically controlled structuring of biotemplates represents also a promising approach for the design of non-biogenic inorganic functional materials applicable in functional devices.
Recently, we successfully employed the wildtype of the tobacco mosaic virus (TMV) as a protein-based biotemplate for the mineralization of the inorganic functional material ZnO. In this case, a reaction solution was used, yielding ZnO particles with a size in the range of 5 nm. The nanoparticles were selectively self-assembled on the virus surface .
Here, we present how the biotemplate formation by self-assembly of TMVs can be triggered by the genetic modification of the virus. For that purpose, monolayers made of the wildtype and several TMV mutants were prepared applying a convective assembly approach. The impact of the genetic modification on the self-assembly performance was studied. Pronounced differences in the surface arrangement of the different TMV variants were observed. The obtained TMV structures with different packing density were mineralized with ZnO. The mineralized ZnO structures directly display the morphologies of the biotemplates. Subsequently, the obtained TMV/ZnO materials were investigated with respect to their functional properties. The semiconducting behavior was studied by the integration of these bio/inorganic hybrids into field effect transistors. The results reveal that the transistor behavior can be modified and tuned by the genetic modification of the virus-based biotemplates. In addition, nacre-like multilayers made of the TMV and ZnO were prepared. The materials show an improved mechanical performance compared to the pure inorganic material due to the presence of the introduced bio/inorganic interfaces.
 P. Atanasova, D. Rothenstein,J. J. Schneider, R. C. Hoffmann, S. Dilfer ,S. Eiben, C. Wege, H. Jeske, J. Bill, Adv. Mater. 23 (2011) 4918
10:15 AM - *GG1.04
Biomimicry at Molecular Scale: Understanding and Designing Interfacial Interactions to Achieve Specific Material Structures
Yu Huang 1
1University of California Los Angeles Los Angeles United StatesShow Abstract
Material formation in nature is precisely controlled in all aspects from crystal nucleation, growth to assembly to deliver superior functions. Specific biomolecule-material interactions have been hypothesized to play important roles in these processes. Proteins, polymers and small molecules have been extensively explored to replicate the degree of control in material formation in vitro and for nonbiogenic materials. However the organic-inorganic interfacial interaction is still far from being understood which hinders the further advancement of biomimetic material formation. In this talk I will share our efforts in decoding the myth of biomolecular specificity to material surface and their roles in controlling crystal nucleation and growth. The selection of facet specific short peptides and their abilities in guiding predictable morphology control of Pt nanocrystals will be first demonstrated. Then detailed experimental and theoretical studies on binding mechanism will be discussed. At the end of the talk, the discovered molecular signature for facet specific adsorption will be applied to design small molecules which can modulate the nucleation/growth of the Pt nanocrystals to deliver the expected nanostructures. These studies open up opportunities in understanding the molecular details of inorganic-organic interface interaction, which can one day lead to the development of a library of molecular functions for biomimetic materials design and engineering.
11:30 AM - GG1.07
Molecular Engineering of Bioactivity at the Bio-NanoMaterial Interfaces
Candan Tamerler 1
1University of Kansas Lawrence United StatesShow Abstract
Nature provides the inspiration for engineering structural- and processing-design criteria for materials. With a growing understanding of the molecular processes involved, bio-inspired strategies are increasingly explored to develop the next generation of biomaterials. There are several challenges in these strategies including replicating the hierarchical organization of biological materials, organization that provides multi-scale structure/property interdependence. The interfacial interactions become critical in tuning the individual components towards the changing functional needs. There is a need for strategies that can control self-organization at a molecular level and thus provide predictability over the biological and inorganic interfaces. In biological systems, proteins conduct various functions through their unique molecular recognition, self-assembly and templating properties. In addition to their role in biomineralization, proteins perform a wide spectrum of additional functions ranging from catalysis to self-repair. The approach includes decoding the peptide-material interactions, and using these foundations to develop self-organized and multifunctional hybrid systems. Genetic engineering and biochemical conjugation are used to produce chimeric peptides and fusion proteins that can controllably bind to a given solid including variety of materials. Here we demonstrate how we utilize the engineered peptides based multifunctional constructs for biological mineralization by developing bio-enabled routes bridging cell programmability to materials as well as biological self-assembly based surface functionalization while reserving the biological activity intact. Our results showed that the peptides can be tailored as major enabling biomolecules in the formation of mineral microlayers on implantable materials with a potential for dental and craniofacial restoration. We also demonstrated that peptide based approach can be applicable to control bioactivity and prevent infections at the implant-host interface. The peptide coatings can be tailored to carry various active entities as targeted delivery constructs. The efficacy of the different sets of multi-functional peptides are demonstrated for various implant materials.These methods will be discussed by introducing orientation and spatial distribution control towards applications in advanced materials fabrication and restorative and regenerative medicine . Multifaceted approach developed provides bio-enabled, single step processes as a key route in simplifying the advanced materials fabrications in biologically friendly conditions. We greatly acknowledge the funding from NIHR-NIAMS, NSF and KU Internal Funds.