Instantaneous Self‐Healing Chitosan Hydrogels with Enhanced Drug Leakage Resistance for Infected Stretchable Wounds Healing

Self-healing hydrogels are intelligent wound dressings to repair structural damage caused by limb movement, demonstrating advantages in stretchable wound management. Chitosan is widely used in the preparation of hydrogels due to the biocompatibility and biodegradability. However, the self-healing efficiency and mechanical strength of chitosan hydrogels are not ideal. To address the issues, three self-healing hydrogels: the single schiff base network hydrogels (OH), the double schiff-base bond network hydrogel (OHD), and borate ester bond/schiff base bond (OHPB) are designed. The self-healing time of OHPB is only 0.7 s measured by real-time electrochemical test, while the self-healing time of OH and OHD is 3.5 h and 1.5 h. Furthermore, OHPB hydrogel exhibits the desirable mechanical strength and tissue adhesion. Following the destruction-repair process, CIP and exosome loaded OHPB (ec⊂OHPB) hydrogel displays approximate 100% drug leakage resistance to achieve long-term antibacterial, cells migration promotion and M2 polarization. ec⊂OHPB hydrogel significantly accelerates infected stretchable wounds healing by relieving inflammation, facilitating angiogenesis and collagen deposition, promoting epidermal remodeling. Consequently, OHPB hydrogel with instantaneous self-healing property and enhanced drug leakage resistance performance makes it possible to broaden the application prospects of chitosan hydrogel dressings.