Synergistic healing of diabetic wounds through photothermal and peroxidase-like activity of heterogeneous Bi₂S₃/Au nanoparticles

Bacterial resistance and biofilm formation around diabetic wounds are major challenges that make the wounds difficult to heal. It is crucial for diabetic wound healing to improve the microenvironment around the wounds. In this study, a novel strategy for diabetic wound healing is developed by combining the peroxidase (POD)-like enzyme activity and photothermal therapy (PTT) to protect against bacterial infections around the wounds. Heterogeneous bismuth sulfide/gold nanoparticles (Bi₂S₃/Au NPs) are synthesized through a two-step wet chemical route. Results show that Bi₂S₃/Au nanozymes display high POD-like enzyme activity and can effectively convert H₂O₂ into ˙OH. The antibacterial rate against <i>S. aureus</i> and <i>E. coli</i> bacteria is 99.8 ± 0.03% and 99.9 ± 0.01%, respectively, in the presence of H₂O₂ under near-infrared light (NIR) irradiation. Animal experiments on infected diabetic wounds demonstrate that the synergistic actions of the Bi₂S₃/Au NPs significantly inhibit the formation of biofilms caused by bacteria, and promote the deposition of collagen and the formation of epithelial and dermal tissue. This study provides a promising solution for innovative therapy of refractory diabetic wounds, which is of great significance for reducing the abuse of antibiotics and the production of drug-resistant bacteria.