(60f) Synthesis and Application of Silk-Inspired Materials

Nature provides extraordinary examples of high-performance polymers with properties often surpassing those of man-made plastics. Protein-based materials are particularly interesting because their palette of amino acid “monomers” and their precisely controlled sequence can give rise to complex properties based on the synergy of diverse intermolecular interactions. Silk fibroin, a class of proteins produced by many insects and arachnids, is an archetypal elastomer with an unrivaled combination of strength and toughness. From a macromolecular perspective, silk fibroins are linear segmented copolymers predominantly consisting of regularly alternating -sheet forming “hard” blocks and flexible “soft” blocks. During spinning, silk fibroins undergo an orchestrated self-assembly process, rapidly transitioning from a soluble protein to a robust material, wherein stiff nanocrystalline -sheet domains reinforce an amorphous matrix. Our research aims to develop new biotic and abiotic synthetic methods to produce silk-mimetic macromolecules with well-defined chemical structures and targeted material properties. These innovations have potential applications in environmental sustainability (e.g. biodegradable plastics for a circular economy) and in healthcare (e.g. materials for tissue engineering and drug release). Furthermore, our work aims to understand and leverage fundamental mechanisms of silk fibroin self-assembly to form new functional materials. For example, we have developed a non-covalent method for generating adherent nanothin silk fibroin coatings on a variety of substrates without surface chemistry or topography limitations. Based on an interfacial self-assembly phenomenon observed in our lab, these coatings completely transform the physicochemical properties of a surface and endow it with new functionality. Our research delves into the interplay of surface-protein and protein-protein interactions enabling coating formation, as well as the use of these coatings for regenerating nerve tissue, preventing bacterial contamination, and releasing biopharmaceuticals from implant surfaces.