Photoresponsive Hydrogel\nDressing Containing Nanoparticles\nwith Excellent Synergetic Photodynamic, Photothermal, and Chemodynamic\nTherapies for Effective Infected Wound Healing

Bacterial resistance to antibiotics can negatively affect\nthe treatment\nof infected skin wounds. The combination of synergistic antibacterial\ntherapies with photodynamic, photothermal, and chemodynamic therapies\nhas been recognized as one of the most promising approaches. In this\nstudy, we have developed MSN@Ce6@MnO<sub>2</sub>–CS/Ag (MCMA)\nnanoparticles to serve as powerful antibacterial agents when exposed\nto both 660 nm visible light and 808 nm near-infrared (NIR) light.\nThrough dual-light irradiation, MCMA can induce hyperthermia and generate\nreactive oxygen species (ROS), leading to a remarkable enhancement\nin photothermal antibacterial effects and accelerating wound healing.\nIt has a peroxidase-like catalytic activity and promotes the generation\nof hydroxyl radicals (·OH) by catalyzing the decomposition of\nH<sub>2</sub>O<sub>2</sub>. <i>In vitro</i> antibacterial\nexperiments demonstrated the excellent antibacterial activity of MCMA.\nThe antibacterial efficacy of MCMA at a concentration of 250 μg\nml<sup>–1</sup> was found to be 99.6 and 100% toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, respectively, under irradiation\nwith an 808 and 660 nm laser. The results of the animal experiments\ndemonstrated that MCMA can effectively accelerate wound healing through\nwound ulceration inhabitation. These findings substantiate the assertion\nthat synthetic MCMA represents an efficacious strategy for bacterial\ninhibition and wound healing.