Flexoelectric polarization unlocks hidden catalytic power in MnO₂ nanoflowers: ROS-mediated pathogen elimination and infected wound regeneration

Chronic bacterial infections are a key pathological factor hindering wound healing, significantly increasing the incidence of wound sepsis. Existing therapeutic strategies exhibit certain limitations, leading to a continuous decline in clinical efficacy. Therefore, there is an urgent need for the development of novel antibacterial materials to mitigate the risks associated with bacterial infections. In this study, a new antibacterial strategy is proposed, utilizing the flexoelectric polarization of manganese dioxide (MnO₂) nanoflowers (NFs) to generate reactive oxygen species (ROS) at the site of infected wounds, achieving in situ and broad-spectrum bacterial eradication. Upon external ultrasound (US) stimulation, the flexoelectric polarization induced in the MnO₂ NFs results in the generation of abundant ROS on the material surface, which disrupts the integrity of bacterial cell membranes, leading to their inactivation. Compared to conventional photodynamic therapy, this strategy achieves higher ROS generation efficiency (65.3% methylene blue (MB) degradation in 25 min) without light dependency. In vitro experiments confirmed the antibacterial efficacy, with the inactivation rates for Escherichia coli and Staphylococcus aureus reaching 66.22% and 70.67%, respectively. Furthermore, excellent antibacterial effects were observed at the site of infected wounds, promoting wound healing. The integration of the flexoelectric effect into material-based antibacterial strategies holds promise for expanding the range of novel antibacterial materials in the future.