Superoxide Radical-Mediated Self-Synthesized Au/MoO_3–<i>x</i> Hybrids with Enhanced Peroxidase-like Activity and Photothermal Effect for Anti-MRSA Therapy

A rapid increase in methicillin-resistant Staphylococcus aureus (MRSA) induced infection has been noticed in recent years and the biofilm formed by MRSA further delays wound healing, causing a high mortality rate. Hence, a safe and effective superoxide radical (O2•-) mediated self-synthesis strategy is developed to prepare Au-doped MoO3-x (Au/MoO3-x) plasmonic-semiconductor hybrid for the elimination of MRSA mediated wound infection. The synthesis mechanism of Au NPs is systematically investigated, proving that O2•- plays a key role in reduction of HAuCl4 into Au NPs in the presence of H2O and O2. Au-doped MoO3-x exhibits the improved photothermal conversion efficiency (∼52.40%) compared with MoO3-x (∼41.11%). Moreover, the peroxidase (POD)-like activity of Au/MoO3-x hybrid is higher than that of MoO3-x NPs, resulting in increased yield of highly toxic ·OH. In combination with the enhanced photothermal and POD-like properties, Au/MoO3-x hybrid achieves efficient elimination of MRSA bacteria with eradication ratio of ∼99.76%. Additionally, the as-prepared Au/MoO3-x NPs exhibit excellent biosafety, which is verified via in vitro and in vivo experiments. This study provides the basis for exploring MoO3-x-based hybrids via a green O2•--mediated self-synthesis approach.