Photothermally enhanced antibacterial and antioxidant dextran hydrogel dressing incorporating tannic acid microparticles for accelerated wound healing

Skin injuries present significant clinical challenges with both physical and psychological impacts, underscoring the urgent need for bioactive dressings capable of orchestrating multi-stage wound repair. To address this, we developed a multifunctional HEOT hydrogel dressing through dynamic covalent crosslinking (Schiff base formation) between oxidized dextran (ODex) and ε-polylysine (EPL), followed by the incorporation of hyaluronic acid (HA) and tannic acid microparticles (TAMP) via ionic and hydrogen bonds. The resulting HEOT hydrogel exhibited robust tissue adhesion, good self-healing ability, and facile injectability, coupled with potent antibacterial efficacy (>93 % inhibition against both E. coli and of S. aureus under NIR irradiation) and significant antioxidant activity ((63.17 ± 0.21) % ROS scavenging under NIR irradiation). Notably, TAMP-mediated photothermal conversion under 808 nm NIR irradiation provided additional therapeutic benefits, including enhanced bacterial eradication, amplified antioxidant effects, and thermal-accelerated tissue regeneration. In vitro assessments confirmed outstanding hemocompatibility (<5 % hemolysis) and cytocompatibility. When applied to S. aureus-infected full-thickness skin wounds, the HEOT hydrogel significantly accelerated wound closure (achieving (90.85 ± 2.97) % closure under NIR irradiation by day 7), stimulating robust neovascularization, and facilitating organized collagen deposition. These findings support the potential applicability of the engineered hydrogel dressing for effective infected wound management.