Interfacial Mo, W-Conjugated Polarization, and Oxygen Vacancies of MoO2/WO3 in Enhanced Microwave Therapy for MRSA-Induced Osteomyelitis

Deep tissue infection, such as osteomyelitis, caused by methicillin-resistant Staphylococcus aureus (MRSA) infection, poses a serious threat to public health and cannot be effectively treated by antibiotics. In this study, we report a microwave (MW)-responsive MoO₂/WO₃ heterojunction that can be utilized to effectively treat MRSA-infected osteomyelitis under MW irradiation because of the enhanced MW thermal effect and MW catalysis of the composite. The underlying mechanism is as follows: A myriad of oxygen vacancies forms on the surface of MoO₂ and WO₃ by deoxidization effect with hydrogen from the decomposition of sodium borohydride, which induces a mass of free electrons on the surface of the composite and consequently promotes a localized surface plasmon resonance effect (LSPR) under MW irradiation. Furthermore, the conjugation of Mo and W at the interface enhances the LSPR effect. Thus, the LSPR effect not only induces the formation of radical oxygen species, thereby enhancing MW catalysis, but also results in the formation of an interfacial electrical field, which strengthens dipole polarization through synergistic action with oxygen vacancies and contributes to better MW thermal effects. The characteristics of MoO₂/WO₃ prove to be promising for the treatment of deep-tissue infections under MW irradiation.