Double‐Dynamic‐Bond Cross‐Linked Hydrogel Adhesive with Cohesion‐Adhesion Enhancement for Emergency Tissue Closure and Infected Wound Healing

The hydrogel adhesives with strong tissue adhesion and biological characteristics are urgently needed for injury sealing and tissue repair. However, the negative correlation between tissue adhesion and the mechanical strength poses a challenge for their practical application. Herein, a bio-inspired cohesive enhancement strategy is developed to prepare the hydrogel adhesive with simultaneously enhanced mechanical strength and tissue adhesion. The double cross-linked network is achieved through the cooperation between polyacrylic acid grafted with N-hydroxy succinimide crosslinked by tannic acid and cohesion-enhanced ion crosslinking of sodium alginate and Ca²⁺. Such a unique structure endows the resultant hydrogel adhesive with excellent tissue adhesion strength and mechanical strength. The hydrogel adhesive is capable of sealing various organs in vitro, and exhibits satisfactory on-demand removability, antibacterial, and antioxidant properties. As a proof of concept, the hydrogel adhesive not only effectively halts non-compressible hemorrhages of beating heart and femoral artery injury models in rats, but also accelerates the healing of infected wound by inhibiting bacteria and reducing inflammation. Overall, this advanced hydrogel adhesive is promising as an emergency rescue adhesive that enables robust tissue closure, timely controlling bleeding, and promoting damaged tissue healing.