Chemical Modification of Silk Proteins: Current Status and Future Prospects

Silk extracted from the cocoon of silkworm has been used as textile materials for thousands of years. Recently, silk has been redefined as a protein-based biomaterial with great potential in biomedical applications owing to its excellent mechanical properties, biocompatibility, and biodegradability. With the advances in silk processing technologies, a broad range of intriguing silk-based functional biomaterials have been made and applied for various biomedical uses. However, most of these materials are based on natural silk proteins without chemical modification, leading to limited control of properties and functions (e.g., biodegradability and bioactivity). A chemical toolbox for modifying the silk proteins is required to achieve versatile silk-based materials with precisely designed properties or functions for different applications. Furthermore, inspired by the traditional fine chemical industry based on synthetic chemistry, developing silk-based fine chemicals with special functions can significantly extend the applications of silk materials, particularly in biomedical fields. This review summarizes the recent progress on chemical modification of silk proteins, focusing on the methodologies and applications. We also discuss the challenges and opportunities of these chemically modified silk proteins.Graphical abstract