(23e) Mechanical Force-Induced Nucleation and Growth of Peptide Nanofibers at Liquid/solid Interfaces

This presentation contains two major findings: one is on mechanical force-induced nucleation and growth of peptide nanofibers on hydrophobic and hydrophilic surfaces, and the other is on new AFM tip based nanolithography. The first part represents the first report where a mechanochemical approach is used for regenerating surface nanoassemblies of biomolecules. The key to this approach is the use of force modulation based on AFM tapping mode to perturb the relatively weak, non-covalent bonds in peptide assembly. This extends the current research in mechanochemistry, where mechanical force is often used to break strong bonds (covalent) and induce chemical reactions or to delivery single molecules. In this study, AFM tip-perturbed or broken peptide fibers can serve as nuclei for subsequent nanofiber growth, resulting in significant local coverage and rearrangement of peptide nanofibers on the surface. The second finding represents a novel nanolithography approach for biomolecular surface patterning. The achievement is a result of combination of solution pH control, amino acid biochemistry and unique peptide-surface interactions. The work reported here will be important to advances in mechanochemistry involving molecular self-assembly and to a large number of biomedical and nanotechnogical applications, e.g., biomolecular templates for nanowire fabrication, enzyme immobilization for chemical sensing, protein/DNA/cell arrays, and model study of self-healing as well as protein conformational diseases.