Photoresponsive Hydrogel Dressing Containing Nanoparticles with Excellent Synergetic Photodynamic, Photothermal, and Chemodynamic Therapies for Effective Infected Wound Healing.

Bacterial resistance to antibiotics can negatively affect the treatment of infected skin wounds. The combination of synergistic antibacterial therapies with photodynamic, photothermal, and chemodynamic therapies has been recognized as one of the most promising approaches. In this study, we have developed MSN@Ce6@MnO₂-CS/Ag (MCMA) nanoparticles to serve as powerful antibacterial agents when exposed to both 660 nm visible light and 808 nm near-infrared (NIR) light. Through dual-light irradiation, MCMA can induce hyperthermia and generate reactive oxygen species (ROS), leading to a remarkable enhancement in photothermal antibacterial effects and accelerating wound healing. It has a peroxidase-like catalytic activity and promotes the generation of hydroxyl radicals (·OH) by catalyzing the decomposition of H₂O₂. In vitro antibacterial experiments demonstrated the excellent antibacterial activity of MCMA. The antibacterial efficacy of MCMA at a concentration of 250 μg ml^-1 was found to be 99.6 and 100% toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, respectively, under irradiation with an 808 and 660 nm laser. The results of the animal experiments demonstrated that MCMA can effectively accelerate wound healing through wound ulceration inhabitation. These findings substantiate the assertion that synthetic MCMA represents an efficacious strategy for bacterial inhibition and wound healing.