Liquid exfoliation of VC nanodots as peroxidase-like nanozymes for photothermal-catalytic synergistic antibacterial treatment.

Nanozymes are effective antibiotics that use reactive oxygen species (ROS) produced by Fenton/Fenton-like reactions to kill bacteria. However, its activity is still not satisfactory and requires large amounts of hydrogen peroxide (HO) with side effects on normal tissues. Herein, ultrasmall VC nanodots (NDs) are successfully constructed by the liquid-phase exfoliation method for photothermal-catalytic synergistic antibacterial treatment. The prepared VC NDs are horseradish peroxidase (HRP)-like nanozymes that can efficiently catalyze HO to produce a large amount of ROS. Unlike traditional HRP-like nanozymes, VC NDs can have a good catalytic effect under slightly acidic conditions (pH=5.5). Moreover, VC NDs have good near-infrared (NIR) absorption and high photothermal conversion efficiency (PTCE, 50.39%), which can be used for photothermal treatment (PTT) of bacteria. In addition, the mild photothermal effect can further enhance the HRP-like catalytic activity of VC NDs, thereby further enhancing the antibacterial performance of VC NDs. In vitro results show that VC NDs can effectively eradicate Escherichia coli (E. coli, gram-negative) and methicillin-resistant Staphylococcus aureus (MRSA, gram-positive) under laser irradiation and the presence of HO, possessing spectral antibacterial properties. More importantly, VC NDs display satisfactory therapeutic effects on wounds infected by MRSA in vivo, and their toxicity is negligible, suggesting that they may have great potential for application as powerful and safe antibacterial agents. This work presents a practical antibacterial strategy by combining PTT and catalytic therapy to achieve efficient treatment of bacteria-infected wounds. STATEMENT OF SIGNIFICANCE: (1) Ultrasmall VC NDs were prepared by the liquid-phase exfoliation method. (2) VC NDs showed good photothermal, catalytic properties. (3) VC NDs achieved satisfactory photothermal-catalytic synergistic antibacterial treatment.