Synergistic “melee attack”: Interfacial band-engineered lamellar heterojunction overcome membrane barriers for enhanced antibacterial therapy

Drug-resistant bacteria, using their dense cell membranes as strong barrier, significantly reduce the efficacy of conventional antibacterial treatments. Phototriggered 2D catalytic nanomaterials have emerged as promising candidates against drug-resistant bacteria by inducing membrane mechanical damage and generating reactive oxygen species (ROS). However, the practical antibacterial efficacy of typical 2D g-C3N4 is severely limited due to the low ROS production. Herein, we report an interfacial band–engineered lamellar heterojunctions (MnCN LHJs) through in situ Mn2O3 growth on g-C3N4. The charges generated in g-C3N4 are stabilised by Mn2O3, minimizing electron–hole recombination and boosting ROS production. Meanwhile, the photocatalytic effect of MnCN LHJs works synergistically with photothermal effects of Mn2O3 to induce a robust 'melee attack' against drug-resistant bacteria. High-resolution synchrotron radiation X-ray tomography directly visualized that MnCN LHJs possessed bacterial trapping capabilities, revealing their ability to induce mechanical damage to bacteria membrane for the first time. Additionally, MnCN LHJs can deplete endogenous glutathione, thereby enhancing ROS generation and weakening the bacterial antioxidant defence system. These combined effects achieve a remarkable bactericidal rate exceeding 98% against MRSA. Notably, MnCN LHJs demonstrate prolonged retention at wound sites, helping to reduce inflammation and promote angiogenesis in infected wounds. This work not only advances interfacial band engineering approach to enhance the photocatalytic performance of g-C3N4 but also underscores the significance of nanomaterial–bacteria interaction in design of next-generation antibacterial materials.