Self-assembled silk fibroin hydrogels: from preparation to biomedical applications

Silk fibroin (SF) from Bombyx mori silkworm has been used as a textile fiber for centuries. In addition, for decades, SF has been used as a suture material. SF's unique properties, such as exceptional host tissue response, appropriate mechanical properties, tunable degradation, simple processing method, and low cost, make it an attractive biomaterial. Accordingly, SF-based hydrogels have attracted much interest in the past years for biomedical applications. The tendency of SF chains to associate and form physical networks has been exploited very frequently in the last decade to prepare self-assembled SF hydrogels. This review describes the methods to prepare self-assembled SF hydrogels focusing on gelation mechanisms and biomedical applications thereof. The advantages and limitations of the methods used to induce SF assembly were discussed. In addition, the use of self-assembled SF hydrogels in interpenetrating network systems and the 3D printing applications were reviewed.