Self-Organized Structures from Nanoparticles and Proteins

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0932823Kotov"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Intellectual Merit:Proteins, DNAs and viruses have the capability to self-assemble into ordered morphologies due to interfacial interactions of these basic biological building blocks. Water-soluble inorganic nanoparticles (NPs) have similar dimensions, chemistries on their surface, and, hence, analogous inter-NP interactions. Indeed, they also have the ability to self-organize. Here, we will explore a hypothesis that NPs and proteins can form hybrid assemblies with new morphologies and topologies, which probably have similarities with those made by proteins and those made by NPs. Besides establishing profound fundamental analogy between two principally different classes of macromolecules, the motivation for this work comes from the need to find methods to make complex NP structures in many instances mimicking the biological counterparts. One characteristic example for this need is the replication of the photosynthetic center of plants and bacteria for solar energy conversion. As well, it will also be interesting to design media-responsive dynamic NP assemblies that can serve as photonic systems, sensors, and micro/nano scale gating systems. Specifically, in this project, the combination of CdTe NPs and Cytochrome C (Cyt C) will be used. Both of the components have strong dipole moments and can potentially self-assemble due to dipole-dipole interaction. The products can be nanowires (NWs), nanosheets (NSs), nanohelixes (NHs) and possibly other superstructures. Once the assemblies are well-characterized for the incorporation of biomolecules, the conformational change of the integrated proteins will be used to tune the overall morphology. The study will also focus on the experimental modulation of the morphological structures of the bio-nanocomposites based upon temperature change and pH effect as two primary control parameters. Conditions leading to reversible transformations of the NP-protein nanocomposite from 1D to 2D and 3D structures will be tested.Broader Impact:The research effort will be complemented by the strong outreach component. The project will provide an energetic and stimulating environment for students with introduction to the toughest problems of chemical engineering and interfacial science. The educational impact of the proposal will be enhanced by the possibility for students to interact with industrial researchers in the development of new applications of nanotechnology. Due to the relative simplicity of materials design techniques as well as chemical safety of the individual components of the composites to be used in the proposal, we plan to involve summer high school students from Michigan thereby disseminating the knowledge on nanotechnology and expanding the breadth of educational impact of the research. University of Michigan is well known for its large-scale diversity effort and recruitment of highly qualified minority students at all levels. This proposal integrates these efforts through campus- and state-wide programs and will have both ethnic and gender minorities immersed in the project. Different protein structure similar to size of NPs and DNA molecules in various lengths will be also employed for similar studies. The assemblies of inorganic materials with DNA will be similarly exploited and characterized for the mechanism of reversible morphologies. By improving the understanding for the bio-nanocomposite formation and further alteration of advanced assemblies will offer the opportunity to design new architectures with higher control compared to the current methods available. Achieving ordered structures by this method in a reversible fashion will also open a new route for designing materials for specific electronic, sensing and diagnostic application.