Microwave catalytic and thermal effects of Ti3C2Tx/ZnO–PPy enhanced by interfacial polarization for rapid treatment of MRSA-induced osteomyelitis

Deep-seated osteomyelitis caused by bacterial infection, particularly methicillin-resistant Staphylococcus aureus (MRSA) infection, poses a significant challenge to treatment. In this study, we propose the utilization of a composite microwave (MW)-responsive polypyrrole-modified titanium carbide/zinc oxide (Ti₃C₂T_x/ZnO–PPy) heterostructure as a potential therapeutic option for MRSA-infected osteomyelitis. In vitro and in vivo experiments show that Ti₃C₂T_x/ZnO–PPy can effectively treat MRSA-induced osteomyelitis under MW irradiation, which is attributed to the enhanced in situ release of MW heat and reactive oxygen species (ROS). Density functional theory and MW network vector analysis further reveal that under MW irradiation, Ti₃C₂T_x/ZnO–PPy generates free electrons that move freely within the heterogeneous interface formed by Ti₃C₂T_x and ZnO, thereby enhancing the accumulation of charges. These charges combine with adsorbed oxygen at the interface to produce ROS. Furthermore, augmented dipole polarization induced by the functional groups on the surface of Ti₃C₂T_x and the interfacial polarization between Ti₃C₂T_x and ZnO contribute to good impedance matching and a favourable attenuation constant in the Ti₃C₂T_x/ZnO–PPy composite, resulting in superior MW thermal properties. Moreover, the polypyrrole-modified composite shows excellent biocompatibility. This efficient antimicrobial system with MW irradiation is expected to offer a viable approach to the management of osteomyelitis.