Dual dynamic bond crosslinked, on-demand removable antimicrobial chitosan hydrogel with superior photothermal...

Bacterial infections often lead to excessive ROS production in the wound, resulting in inadequate oxygen supply and nutrient deficiencies, which trigger a severe inflammatory response and delay wound healing. In this study, a multifunctional carboxymethyl chitosan(CMCS)-3,4,5-trihydroxybenzaldehyde(THBA)@Fe (CTF) hydrogel was constructed based on the synergistic effect of the dynamic Schiff base reaction and metal coordination. The material formed a dynamic Schiff base bond with the CMCS amino group through the aldehyde group of THBA and coordinated with Fe³⁺ to construct a dual-network structure. Experiments have shown that CTF hydrogels exhibit excellent self-healing, on-demand removal, pH responsiveness, and antimicrobial properties. It can effectively scavenge ROS while catalyzing the decomposition of H₂O₂ to release oxygen through catalase-like activity, significantly alleviating the hypoxic state of the wound. Animal experiments demonstrated its ability to accelerate infected wound healing by promoting angiogenesis and collagen deposition, as well as modulating key genes involved in cell migration, energy metabolism, and wound repair. This antibiotic-free and multifunctional hydrogel with integrated antioxidant‑oxygenation-photothermal antimicrobial properties offers a new therapeutic strategy for wound healing.