Rapid In Situ Deposition of Iron-Chelated Polydopamine Coating on the Polyacrylamide Hydrogel Dressings for Combined Photothermal and Chemodynamic Therapy of Skin Wound Infection

Pathogenic bacterial infections of skin wounds have caused a significant threat to clinical treatment and human life safety. Here, we develop a bactericidal hydrogel dressing consisting of a polyacrylamide (PAM) hydrogel framework with in situ surface-deposition of iron-dopped polydopamine (FePDA). The prepared hydrogel dressing (FePDA-PAM) has a compact surface, good tensile strength, and excellent elastic recovery ability. The introduction of Fe³⁺ ions improve the photothermal therapy (PTT) efficiency of the PDA and endow the hydrogel dressing with chemodynamic therapy (CDT) properties. In vitro experiments show that the antibacterial effect of FePDA-PAM hydrogel on Staphylococcus aureus reach nearly 100% under the combined action of H₂O₂ and 808 nm near-infrared (NIR) laser, indicating an excellent combined antibacterial property of PTT and CDT. Furthermore, the FePDA-PAM + H₂O₂ + NIR treatment group in the in vivo antibacterial experiments displays lowest relative wound area and optimal wound healing within 5 days of treatment, thereby indicating the intensive skin wound disinfection. To summarize, the FePDA-PAM hydrogel has simple preparation and good biosafety. It may serve as a potential wound dressing for the combined PTT/CDT dual-mode antibacterial therapy.