Self-Assembled Nanoflowers Realizes Synergistic Sterilization with Photothermal and Chemical Kinetics Therapy

Wounds caused by bacterial infections have become a major challenge in the medical field; however, the overuse of antibiotics has led to increased resistance and bioaccumulation. Therefore, it is urgent to develop an antibacterial agent with excellent antibacterial properties and biosafety. Here, we designed an antibacterial platform that combines photothermal and chemical kinetics therapies. Platinum-cobalt (PtCo) bimetallic nanoparticles (NPs) were first prepared, and then PtCo@MnO₂ nanoflowers were obtained by adding MES buffer solution and KMnO₄ to the PtCo bimetallic nanoparticle suspension using ultrasound. When light strikes metal NPs, they can strongly absorb the photon energy, resulting in photothermal properties. In addition, Pt and Co were used as the oxidase mimics, and MnO₂ was used as the catalase mimic. In summary, the photothermal capacity of PtCo@MnO₂ nanoflowers with rough surfaces can effectively disrupt the permeability of the bacterial cell membranes. Further, by catalyzing H₂O₂, PtCo@MnO₂ nanoflowers can generate large amounts of hydroxyl free radicals, which can damage bacterial cell membranes, proteins, and DNA. In addition, MnO₂ can effectively alleviate the hypoxic environment of the bacterially infected areas and activate deep bacteria, thus achieving the goal of complete sterilization. The in vitro and in vivo results showed that PtCo@MnO₂ displayed excellent antibacterial properties and good biocompatibility.