Newly emerged two-dimensional material, black phosphorus (BP) shows promising applications in many fields owing to its superior properties. Despite the biological effects of BP were studied, its environmental impacts have not yet received enough attention. In this study, the bacterial toxicity of exfoliated BP nanosheets was for the first time evaluated against two model bacteria strains, Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis). By monitoring the bacterial growth curve and colony counting, the bacterial toxicity of BP nanosheets was examined. Higher toxicity was induced for Gram-negative E. coli compared to Gram-positive B. subtilis after 6 h treatment, which was reversed at 12 h due to membrane self-healing of E. coli. The bacterial toxicity followed a time- and concentration-dependent fashion, with a maximum bactericidal efficiency of 91.65% and 99.69% for E. coli and B. subtilis, respectively, after 12 h exposure. Reactive oxygen species (ROS)-dependent oxidative stress and membrane damage were the main bactericidal mechanisms as proved by fluorescence microscopy, flow cytometry, scanning electron microscopy (SEM), and Lactate dehydrogenase (LDH) assay. This study indicates the potential environmental risk of BP nanosheets and the data from this work will guide their safety applications in the future.

新出现的二维材料黑磷（BP）由于其优越的性能而在许多领域中显示出令人鼓舞的应用。尽管已研究了BP的生物学效应，但其对环境的影响尚未引起足够的重视。在这项研究中，首次评估了脱落的BP纳米片对两种模型细菌菌株革兰氏阴性大肠杆菌（E. coli）和革兰氏阳性枯草芽孢杆菌（B. subtilis）的细菌毒性。通过监测细菌生长曲线和菌落计数，检查了BP纳米片的细菌毒性。与革兰氏阳性枯草芽孢杆菌相比，革兰氏阴性大肠杆菌诱导出更高的毒性处理6小时后，由于大肠杆菌的膜自我修复，在12小时后逆转。细菌毒性遵循时间和浓度依赖性，暴露12 h后对大肠杆菌和枯草芽孢杆菌的最大杀菌效率分别为91.65％和99.69％。荧光显微镜，流式细胞仪，扫描电子显微镜（SEM）和乳酸脱氢酶（LDH）分析证明，活性氧（ROS）依赖性氧化应激和膜损伤是主要的杀菌机理。这项研究表明了BP纳米片的潜在环境风险，这项工作的数据将指导其未来的安全应用。