Multifunctional light-activated hydrogel: Synergistic photothermal sterilization and tissue microenvironment engineering for enhanced wound healing.

Multifunctional wound dressings are critical for meeting complex clinical needs. Herein, we prepared a mechanically excellent nanocomposite hydrogel (PGC-ZnO) by incorporating ZnO NPs into a polyacrylamide/gelatine/carboxymethyl chitosan network. It exhibits outstanding adhesive strength (6.5 ± 1.2 kPa) and toughness (32 kJ·m-3) for stable coverage, along with a high swelling capacity (1500% ± 35%) for effective exudate management. Antibacterial tests against clinical E. coli and S. aureus show>95% bactericidal rates within 10 min of NIR irradiation, attributed to synergistic photothermal ablation (ΔT > 43 °C) and ZnO-mediated bactericidal action. Biocompatibility (per ISO 10993-5) reveals >95% L929 cell viability and negligible hemolysis (<3%). In full-thickness murine wounds, PGC-ZnO accelerated epithelialization to 98.2% ± 2.1% by day 14 (vs. 68.5% ± 5.3% in controls). Histological analysis showed tissue thickness more similar to that of normal rat skin, with increased neovascularization and enhanced M2 macrophage polarization. This multifunctional platform meets key wound-regeneration requirements through balanced mechanical integrity, fluid handling, bactericidal activity, and biocompatibility. Overall, PGC-ZnO hydrogel, as an advanced multifunctional wound dressing, has broad prospects for clinical translation.