MXene-Based Dual Functional Nanocomposite with Photothermal Nanozyme Catalytic Activity to Fight Bacterial Infections

Bacterial infections are common complications for diabetic wounds and represent a considerable challenge for wound therapy. Diabetic wound infections differ from those of normal wounds. Owing to the special microenvironment around them, diabetic wounds are more susceptible to infection and are difficult to heal. Nanozymes are of great significance to treat diabetic wound bacterial infections through unique catalytic activities, particularly for controlling drugresistant bacteria. However, their intrinsically low catalytic activity largely restricts their bactericidal function. Therefore, it is crucial to design and develop novel antibacterial modalities with multiple mechanisms of action. In this study, we design and synthesize a CeO2/Nb2C nanocomposite with dual functions of peroxidase activity and an excellent near-infrared (NIR) photothermal property. Under 808 nm laser irradiation, the CeO2/Nb2C nanocomposite produced a photothermal antibacterial effect and simultaneously displayed a synergistic enzyme catalytic property, thereby killing bacteria in a sustained manner with more than 80% sterilization ratio. The CeO2/Nb2C nanocomposite could accelerate the recovery of diabetic wounds when the skin lesions infected with methicillin-resistant Staphylococcus aureus (MRSA) were irradiated with an 808 nm laser in a diabetic mouse model. An RNA sequencing assay was used to profile the dynamic transcriptome of MRSA. The data set reveals that bacteria experience dysfunction in energy metabolism, cell morphology, and oxidative stress systems during the treatment with CeO2/ Nb2C nanocomposite under NIR irradiation, which further affects their survival. Moreover, the CeO2/Nb2C nanocomposite exhibits good biosafety in vitro and in vivo, which indicates their potency as antibacterial agents. This study provides a novel antibacterial strategy by the combination of the catalytic sterilization with the NIR photothermal activity of nanozymes for the effective treatment of MRSA-related diabetic wound infection.