Mussel-Inspired Adhesive and Tough Hydrogel Based on Silk-Triggered Dopamine Polymerization for Wound Healing

Tissue engineering is a great alternative to repair and regenerate damaged tissues and organs. Hydrogels are promising materials for tissue repair, but optimizing their various functions-such as adhesion, mechanical properties, and vascularization-to suit the complexity of different organs and tissues remains a significant challenge. In this study, we explore a tough and adhesive polydopamine (PDA)-silk-polyacrylamide (PAM) hydrogel inspired by the mussel-inspired adhesion of PDA and the vascularization potential of silk. Through a Schiff base reaction, self-polymerization occurs between the free dopamine and the conjugated dopamine on the silk chains, resulting in the formation of a PDA/silk prepolymer. The presence of PDA in the prepolymer endows the resulting PDA-silk-PAM hydrogel with excellent adhesiveness, strong mechanical properties, and good water absorption. By adjusting the degree of crosslinking, the hydrogel also demonstrates impressive deformability, making it suitable for engineering thicker and more complex tissues and organs. Moreover, benefiting from the vascularization capabilities of silk and the adhesive properties of PDA, the PDA-silk-PAM hydrogel effectively promotes vascularization and accelerates wound healing in full-thickness skin wounds on the backs of Sprague-Dawley rats. Overall, our study provides a straightforward approach to create versatile medical hydrogel with strong potential for clinical applications.