Comparative study of the cytotoxic and genotoxic effects of titanium oxide and aluminium oxide nanoparticles in Chinese hamster ovary (CHO-K1) cells

Abstract The aim of this study was to analyze the cytotoxicity and genotoxicity of titanium oxide (TiO 2 ) and aluminium oxide (Al 2 O 3 ) nanoparticles (NPs) on Chinese hamster ovary (CHO-K1) cells using neutral red (NR), mitochondrial activity (by MTT assay), sister chromatid exchange (SCE), micronucleus (MN) formation, and cell cycle kinetics techniques. Results showed a dose-related cytotoxic effect evidenced after 24 h by changes in lysosomal and mitochondrial dehydrogenase activity. Interestingly, transmission electronic microscopy (TEM) showed the formation of perinuclear vesicles in CHO-K1 cells after treatment with both NPs during 24 h but no NP was detected in the nuclei. Genotoxic effects were shown by MN frequencies which significantly increased at 0.5 and 1 μg/mL TiO 2 and 0.5–10 μg/mL Al 2 O 3 . SCE frequencies were higher for cells treated with 1–5 μg/mL TiO 2 . The absence of metaphases evidenced cytotoxicity for higher concentrations of TiO 2 . No SCE induction was achieved after treatment with 1–25 μg/mL Al 2 O 3 . In conclusion, findings showed cytotoxic and genotoxic effects of TiO 2 and Al 2 O 3 NPs on CHO-K1 cells. Possible causes of controversial reports are discussed further on.