Synergistic photothermal and photodynamic therapy to promote bacteria-infected wound healing using ZnO@PDA/Ag-integrated waterborne polyurethane films

Abstract

Light-induced antibacterial effectsaim to overcome the limitations of antibiotic-resistant bacteria and provide an effective solution for wound healing applications. This research focuses on developing a multifunctional wound dressing based on waterborne polyurethane (WPU) adorned with a hybrid photo nanosensitizer (ZnO@PDA/Ag) that demonstratesnear-infrared (NIR)-triggered synergistic photothermal and photodynamic effect.Through a facile synthesis process, zinc oxide (ZnO) nanoparticles were coated with polydopamine (PDA) to enhance biocompatibility, photothermic effect, and charge transfer efficiency due to surface sensitization and passivation strategy. The synthesis was followed by the in-situ reduction and decoration of plasmon silver nanoparticles (Ag NPs) to augment photodynamic activity. The structure, chemical composition, and morphology of ZnO@PDA/Agnanosensitizer were examined and the results confirmed the successful synthesis. Furthermore, based on photo-thermal and fluorescence signal measurementsunder near-infrared (NIR) irradiation, the ZnO@PDA/Ag nanoparticles in aqueous dispersions exhibit effective light-to-heat conversion, as well as a strong ability for NIR-induced singlet oxygen generation.The WPU films incorporating the ZnO@PDA/Ag nanosensitizer exhibit complete phototherapy inhibition of both gram-negative E. coli and gram-positive S. aureus bacteria.In addition, the films exhibited an appropriate biocompatibility in contact with L929 fibroblast cells.Moreover, in vivo studies in a rat wound model demonstrated accelerated wound healing and tissue regeneration with the application of ZnO@PDA/Ag in WPU nanocomposite film, particularly under NIR light irradiation. Histological analysis confirmed the formation of mature epithelial layers and minimal inflammatory response, indicating the potential of this film for clinical wound management.