Cytotoxicity of vanadium oxide nanoparticles and titanium dioxide-coated vanadium oxide nanoparticles to human lung cells.

Due to excellent metal-insulator transition property, vanadium dioxide nanoparticles (VO2 NPs)-based nanomaterials are extensively studied and applied in various fields, and thus draw safety concerns of VO2 NPs exposure through various routes. Herein, the cytotoxicity of VO2 NPs (N-VO2 ) and titanium dioxide-coated VO2 NPs (T-VO2 ) to typical human lung cell lines (A549 and BEAS-2B) was studied by using a series of biological assays. It was found that both VO2 NPs induced a dose-dependent cytotoxicity, and the two cell lines displayed similar sensitivity to VO2 NPs. Under the same conditions, T-VO2 NPs showed slightly lower cytotoxicity than N-VO2 in both cells, indicating the surface coating of titanium dioxide mitigated the toxicity of VO2 NPs. Titanium dioxide coating changed the surface property of VO2 NPs and reduced the vanadium release of particles, and thus helped lowing the toxicity of VO2 NPs. The induced cell viability loss was attributed to apoptosis and proliferation inhibition, which were supported by the assays of apoptosis, mitochondrial membrane damage, caspase-3 level, and cell cycle arrest. The oxidative stress, i.e., enhanced reactive oxygen species generation and suppressed reduced glutathione , in A549 and BEAS-2B cells was one of the major mechanisms of the cytotoxicity of VO2 NPs. These findings provide safety guidance for the practical applications of vanadium dioxide-based materials.