The research objective of this award is to understand and model the helical structure and mechanics of amyloid fibrils, and the stability and mechanical energy storage in helical zinc oxide nanostructures. Because these structures exist on a scale comparable to interatomic distances, atomistic detail is essential to understanding their behavior. The planned nanomechanical computations are prohibitive with current quantum methods, which are dependent on the translational symmetry of crystalline solids. They become possible, however, with the new objective molecular dynamics method coupled with the self-consistent-charge density-functional tight-binding. This coupling relies on a proposed generalization of the Ewald method to a helical charge distribution. Preliminary results indicate that this generalization is feasible and could enable efficient nanostructure and biomolecule simulations.
If successful, the methodology will allow for the first time the evaluation of electrostatic fields generated by discrete charge distributions over helical structures in modern materials and life sciences on a quantitative level. The amyloid fibril studies, aimed at understanding key atomistic details, mechanical properties and correlations between polymorphism and mechanical response, will help elucidate molecular mechanisms in Alzheimer's and other prion diseases. Also, they will have implications for the meso-scale modeling of amyloid fibrils and for the biomimetic development of nanomaterials. The helical zinc oxide nanobelts simulations, focused on super elasticity, buckling, fracture, and the transfer of mechanical into electric energy, will produce a phenomenological Landau model useful for designing power nano-generators. The planned research is integrated with an educational program that facilitates the incorporation of nanomechanics into the engineering curriculum; it is also accompanied by efforts to encourage participation of underrepresented minorities. A cyber-module will illustrate for the Minnesota public underlying effects related to prion diseases, and mechanisms responsible for nano-energy storage. This module will be made available to the Minnesota Science Museum.
