Objective To compare the difference between nano-and micro-TiO2 particles in their cytotoxicity and DNA damage effects on A549 cells.
Methods A549 human lung adenocarcinoma cells were exposed to different concentrations of these two particles (0, 25, 50, 100 and 200 μg/mL)separately, the methyl thiazolyl tetrazolium (MTT)assay and the single cell gel electrophoresis (comet assay) were applied to measure the cytotoxicity and DNA damage.
Results It showed that the developed trend of the cytotoxicity induced by nano-TiO2 and micro-TiO2 was similar, but at the same level, nano-TiO2 induced greater damage than the micro-TiO2. For example, after 12 h treatment, nano-TiO2 in a dose of 200 μg/mL inhibited the viability of A549 cells significantly compared with the micro-TiO2 group. In addition, compared to the control group, the tail DNA content, Olive tail moment and comet tail length of the nano-TiO2 group increased significantly (P<0.05); whereas these indices in micro-TiO2 group did not change.
Conclusion Our data demonstrates that nano-TiO2 particles possess a toxic potential towards A549 cells which may be significantly higher than micro ones; the toxic effects occur earlier in time and lower in dose compared with micro-TiO2, and nano-TiO2 particles can induce DNA damage, but micro-ones do not. It is shown that the nano-and micro-TiO2 particles have some differences in toxicity and toxic properties.
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