DAHA/CMCS/Ag@PDA dual-dynamic crosslinked injectable hydrogels with NIR-II photothermal synergistic antibacterial and antioxidant properties for accelerated healing of bacterial-infected wounds

Bacterial infections and excessive oxidative stress severely impede the wound healing process, and the development of multifunctional wound dressings with antibacterial, antioxidant, and biosafety properties is of great clinical significance. In this study, DAHA/CMCS/Ag@PDA (DCA) injectable hydrogels were successfully prepared by dual-dynamic crosslinking of Schiff base and hydrogen bonds. Dopamine graft-modified oxidized hyaluronic acid (DAHA) and carboxymethyl chitosan (CMCS) constructed a dynamic and reversible cross-linking network of the hydrogel, which endowed the hydrogel with excellent injectable, self-healing, shape-adaptive, and high adhesion properties. Meanwhile, DAHA and Ag@PDA, which are rich in catechol groups, provided the hydrogels with highly efficient synergistic antioxidant properties, which could effectively scavenge various free radicals. In addition, the loading of Ag@PDA endowed the hydrogel with excellent Ag + release and NIR-II photothermal conversion properties, and DCA2 could realize efficient killing (99.6%) of S. aureus and E. coli through the synergistic action of Ag  +  slow release and NIR-II photothermal, which could effectively promote the healing of bacterial-infected wounds. In conclusion, this study provides a new design strategy for hydrogel dressings for the treatment of bacterial-infected wound healing through the multifunctional integration of NIR-II photothermal synergistic antibacterial and antioxidant properties.