Pathologically Responsive Au@Ag Nanocomposite Spray-Coated Hydrogel Dressing for Accelerated Healing of Infected Wounds.

Infected wounds present a major clinical challenge due to the increasing prevalence of antibiotic resistance and the complex interplay of factors that impede tissue regeneration. To address this, we developed a pathologically responsive, sprayable hydrogel dressing incorporating gold-core silver-shell nanorod (Au@Ag NR) nanocomposites to accelerate infected wound healing. The hydrogel, composed of poly(vinyl alcohol) (PVA) and carboxylated chitosan (CCS), responds to elevated hydrogen peroxide (H2O2) levels characteristic of infected wound microenvironments. Upon exposure to pathological H2O2, the Ag shell of the Au@Ag NRs undergoes oxidative etching, releasing silver ions (Ag+) for potent antibacterial action while simultaneously exposing the Au core for subsequent photothermal therapy upon second near-infrared (NIR-II) irradiation. In vitro studies demonstrated significant antibacterial efficacy against both Escherichia coli and Staphylococcus aureus, while in vivo assessments using a mouse model of infected wound healing revealed enhanced angiogenesis, reduced inflammation, and accelerated wound closure compared to control treatments. Synergistic Ag+ release and NIR-triggered photothermal ablation led to superior antibacterial and wound healing outcomes. These findings suggest that the sprayable hydrogel shows promise as a clinically translatable strategy for the effective management of severely infected wounds.