Mimicry of silk utilizing synthetic polypeptides

For thousands of years, ‘silk’ and silk-based materials have played an important role for mankind. Today, silk-based materials increasingly find use in novel application areas such as biomedical and advanced technologies. However, natural silks show limitations. To overcome these limitations, chemical polymerization methods have been developed that provide potential avenues to synthetic materials with silk-like features. This article summarizes the physicochemical properties of silks and reviews how the structure-property relationships of silks have inspired material design, for example, by integration of β-sheet forming polypeptide regions. Strategies that utilize N-carboxyanhydride ring-opening polymerization (NCA ROP) for polypeptide synthesis are the primary focus of this review as they provide a versatile platform for polypeptide engineering. Finally, the prospects of silk-inspired material design, such as amorphous polymers featuring β-sheet structures, for the design of high performance polymers are discussed.