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 b-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 b-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 and viral contamination, and releasing biopharmaceuticals from implant surfaces.
Dr. Helen Zha received her B.Sc. (2007) from MIT and her Ph.D. (2013) from Northwestern University in Materials Science & Engineering. After pursuing postdoctoral research at Eindhoven University of Technology and UC Berkeley, Helen started as a tenure-track assistant professor at Rensselaer Polytechnic Institute in the Department of Chemical & Biological Engineering in 2018. She is an affiliate faculty in the Biochemistry and Biophysics graduate program and a member of the Center for Engineering and Precision Medicine. Additionally, Helen is an Associate Director of the recently founded NY Fashion Innovation Center. Helen’s research focuses on the study of natural materials and the synthesis of biomimetic materials. Helen has received the National Science Foundation CAREER Award and the National Institutes of Health R35 MIRA Early Career grant. She is a Scialog fellow and was named an Emerging Investigator by RSC Biomaterials Sciences in 2019. Externally, Helen was the 2023 Chair of the Biomaterials program area of the American Institute of Chemical Engineers. She is also an active member of the American Chemical Society and the Society for Biomaterials.