A dual-modal ROS generator based on multifunctional PDA–MnO2@Ce6 nanozymes for synergistic chemo-photodynamic antibacterial therapy

The rapid emergence of drug-resistant bacteria has attracted great attention to exploring advanced antibacterial methods. However, single-modal antibacterial therapy cannot easily eliminate drug-resistant bacteria completely due to its low efficacy. Therefore, it is essential to achieve multi-modal antibacterial therapy effectively. Herein, a dual-modal ROS generator was designed based on photosensitive PDA–MnO2@Ce6/liposome (PMCL) nanozymes for synergistic chemo-photodynamic therapy. PMCL nanozymes adhere to bacteria through liposome–membrane fusion. Meanwhile, PMCL catalyzes endogenous hydrogen peroxide (H2O2) to generate hydroxyl radicals (·OH) and singlet oxygen (1O2) under laser irradiation. Furthermore, the photothermal effect can accelerate the generation of ROS. Based on dual-enzyme activities (mimicking peroxidase and catalase) and photodynamic properties, PMCL achieves powerful antibacterial efficacy and mature bacterial biofilm eradication. With the synergistic chemo-photodynamic effects, bacterial populations decrease by >99.76% against Gram-positive S. aureus and Gram-negative E. coli. Notably, the synergistic antibacterial properties of PMCL nanozymes are further explored using a mouse wound model of S. aureus infection. This work fabricated an efficient dual-modal ROS generator to kill bacteria, further providing a new strategy for treating wound infection.