Edge-selective covalent passivation of black phosphorus nanosheets by fullerene C70 toward enhanced antimicrobial performance

In the fight against bacterial infection, conventional antibiotic treatment encounters the formidable challenges of drug resistance and sluggish development. Non-metallic two-dimensional (2D) nanomaterials such as black phosphorus (BP) have emerged as promising non-antibiotic antimicrobial candidates due to its peculiar physiochemical properties, but face hurdles including low ambient stability and limited antibacterial activity, hindering its widespread utilization in disinfection. Herein, few-layer BP nanosheets (BPNSs) were covalently passivated by edge-selectively grafting fullerene C70 via a one-step solid-state mechanochemical route, and for the first time the covalently functionalized BPNSs is employed in disinfection. Fullerene edge-selective covalent passivation not only effectively overcomes the obstacles of poor ambient stability, but also substantially enhances the antibacterial activities of BPNSs. The BPNSs-C70 hybrid (denoted as BPNSs-C70) was applied as a novel non-metallic and non-antibiotic nano-antibacterial agent. Under 660 nm visible light irradiation, BPNSs-C70 demonstrates high generation capacity of reactive oxygen species (ROS), resulting in boosted in vitro and in vivo antibacterial efficacies against methicillin-resistant Staphylococcus aureus (MRSA) relative to the pristine BPNSs with exceptional biocompatibility. The significantly enhanced antibacterial performance of BPNSs-C70 is attributed to the synergistically improved singlet oxygen (1O2) and hydroxyl radicals (center dot OH) generation originated from the intramolecular electron transfer from BPNSs to C70.