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.