Oxygen vacancy-enhanced microwave catalysis of Zn–Fe spinel for implant-related infections

Implant-related infections (IRIs) pose a major challenge in orthopedic applications due to the persistence of biofilms, which are highly resistant to conventional antibiotics. This study introduces oxygen vacancy-engineered Zn–Fe spinel nanoparticles as microwave-responsive antibacterial agents. The oxygen vacancies in the spinel structure enhance reactive oxygen species (ROS) generation under microwave irradiation, providing a dual-mode antibacterial mechanism of thermal and oxidative stress. Zn–Fe spinel nanoparticles were synthesized using a sol–gel method and evaluated for their antibacterial efficacy against Staphylococcus aureus biofilms. Under microwave irradiation, the Zn–Fe spinel demonstrated significant biofilm disruption and bacterial eradication. Mechanistic studies revealed that oxygen vacancies promoted ROS generation, leading to bacterial membrane damage. In vivo experiments using a mouse infection model confirmed the material's antibacterial efficacy and biocompatibility, with no observed toxicity. This study highlights the potential of oxygen vacancy-enhanced Zn–Fe spinel as a microwave-assisted, antibiotic-free strategy for treating deep-seated infections associated with orthopedic implants.