The Cytotoxicity of Layered Black Phosphorus

Black phosphorus (BP), the latest addition to the family of 2D layered materials, has attracted much interest owing to potential optoelectronics, nanoelectronics, and biomedicine applications. Little is known about its toxicity, such as whether it could be as toxic as white phosphorus. In response to the possibility of BP employment into commercial products and biomedical devices, its cytotoxicity to human lung carcinoma epithelial cells (A549) was investigated. Following a 24h exposure of the cells with different BP concentrations, cell viability assessments were conducted using water-soluble tetrazolium salt (WST-8) and methylthiazolyldiphenyltetrazolium bromide (MTT) assays. The toxicological effects were found to be dose-dependent, with BP reducing cell viabilities to 48 % (WST-8) and 34 % (MTT) at 50μg mL^-1 exposure. This toxicity was observed to be generally intermediate between that of graphene oxides and exfoliated transition-metal dichalcogenides (MoS₂, WS₂, WSe₂). The relatively low toxicity paves the way to utilization of black phosphorus.