Genotoxicity, cytotoxicity and reactive oxygen species induced by single-walled carbon nanotubes and C60 fullerenes in the FE1-MutaTMMouse lung epithelial cells

Viability, cell cycle effects, genotoxicity, reactive oxygen species production, and mutagenicity of C60 fullerenes (C60) and single-walled carbon nanotubes (SWCNT) were assessed in the FE1-MutaTMMouse lung epithelial cell line. None of these particles induced cell death within 24 hr at doses between 0 and 200 g/ml or during long-term subculture exposure (576 hr) at 100 g/ml, as determined by two different assays. However, cell proliferation was slower with SWCNT exposure and a larger fraction of the cells were in the G1 phase. Exposure to carbon black resulted in the greatest reactive oxygen species generation followed by SWCNT and C60 in both cellular and cell-free particle suspensions. C60 and SWCNT did not increase the level of strand breaks, but significantly increased the level of FPG sensitive sites/oxidized purines (22 and 56%, respectively) determined by the comet assay. The mutant frequency in the cII gene was unaffected by 576 hr of exposure to either 100 g/ml C60 or SWCNT when compared with control incubations, whereas we have previously reported that carbon black and diesel exhaust particles induce mutations using an identical exposure scenario. These results indicate that SWCNT and C60 are less genotoxic in vitro than carbon black and diesel exhaust particles