A ·OH self-suppling and dual regulation hybrid nanozyme combined with photothermal therapy to eliminate biofilms and eradicate infections

Limited by local H2O2 concentration and GSH hindrance, chemodynamic therapy (CDT) has poor antibacterial efficiency, and the pro-inflammatory response caused by CDT is often ignored. Here, a hybrid nanozyme (Fe3O4-CaO2-PDA) was synthesized, which has dual regulatory functions of ·OH and GSH, there are two stages in clearing the infection: treatment and repair. In the treatment stage, stimulated by the photothermal generated by near-infrared light (NIR), it rapidly releases a large amount of ·OH and further enhances CDT by decreasing the local GSH concentration to achieve a rapid antimicrobial effect. In the repair stage, the PDA removes the local residual ·OH, prevents over-aggregation of inflammatory cells, and regulates pro-inflammatory responses. In vitro antibacterial experiments showed that the killing rates of the hybrid nanozyme against S. aureus and E. coli were 90% and 92% respectively. At the same time, the DCFH-DA fluorescence experiment showed that the ·OH concentration was significantly controlled. in vivo, due to the function of control ·OH, nanozymes show the ability to promote collagen regeneration and regulate inflammation. In summary, this study proposed a synergistic multiple antibacterial strategy and successfully constructed a PTT-enhanced multifunctional hybrid nanozyme for efficient CDT anti-infective treatment.