Iron oxide nanoparticles with photothermal performance and enhanced nanozyme activity for bacteria-infected wound therapy

Metal-based nanomaterials usually have broad-spectrum antibacterial properties, low biological toxicity and no drug resistance due to their intrinsic enzyme-like catalytic properties and external field (magnetic, thermal, acoustic, optical and electrical) responsiveness. Herein, iron oxide (Fe3O4) nanoparticles (IONPs) synthesized by us have good biosafety, excellent photothermal conversion ability and peroxidase-like catalytic activity, which can be used to construct a photothermal-enzymes combined antibacterial treatment platform. IONPs with peroxide-like catalytic activity can induce H2O2 to catalyze the production of •OH in a slightly acidic environment, thus achieving certain bactericidal effects and increasing the sensitivity of bacteria to heat. When stimulated by near-infrared light, the photothermal effect could destroy bacterial cell membranes, resulting in cleavage and inactivation of bacterial protein, DNA or RNA. Meanwhile, it can also improve the catalytic activity of peroxidase-like and promote IONPs to catalyze the production of more •OH for killing bacteria. After IONPs synergistic treatment, the antibacterial rate of Escherichia coli and Staphylococcus aureus reached nearly 100%. It also has an obvious killing effect on bacteria in infected wounds of mice and can effectively promote the healing of S. aureus-infected wounds, which has great application potential in clinical anti-infection treatment.