Comparative study of cyto‐ and genotoxic potential with mechanistic insights of tungsten oxide nano‐ and microparticles in lung carcinoma cells

The exigency of semiconductor and super capacitor tungsten oxide nanoparticles (WO3 NPs) is increasing in various sectors. However, limited information on their toxicity and biological interactions are available. Hence, we explored the underlying mechanisms of toxicity induced by WO3 NPs and their microparticles (MPs) using different concentrations (0–300 μg ml–1) in human lung carcinoma (A549) cells. The mean size of WO3 NPs and MPs by transmission electron microscopy was 53.84 nm and 3.88 μm, respectively. WO3 NPs induced reduction in cell viability, membrane damage and the degree of induction was size‐ and dose‐dependent. There was a significant increase in the percentage tail DNA and micronuclei formation at 200 and 300 μg ml–1 after 24 hours of exposure. The DNA damage induced by WO3 NPs could be attributed to increased oxidative stress and inflammation through reactive oxygen species generation, which correlated with the depletion of reduced glutathione content, catalase and an increase in malondialdehyde levels. Cellular uptake studies unveiled that both the particles were attached/surrounded to the cell membrane according to their size. In addition, NP inhibited the progression of the cell cycle in the G2/M phase. Other studies such as caspase‐9 and ‐3 and Annexin‐V‐fluorescein isothiocyanate revealed that NPs induced intrinsic apoptotic cell death at 200 and 300 μg ml–1 concentrations. However, in comparison to NPs, WO3 MPs did not incite any toxic effects at the tested concentrations. Under these experimental conditions, the no‐observed‐significant‐effect level of WO3 NPs was determined to be ≤200 μg ml–1 in A549 cells. We explored the underlying mechanism of toxicity induced by tungsten oxide nanoparticles (WO3 NPs) and microparticles (MPs) in A549 cells. A size‐ and dose‐dependent cyto‐ and genotoxic effect of WO3 NPs at higher concentrations was observed. WO3 NPs induced toxicity in lung cells via reactive oxygen species generation and an oxidative stress‐mediated caspase‐dependent apoptotic pathway. The no‐observed‐significant‐effect level of WO3 NPs was determined to be ≤200 μg ml–1. However, WO3 MPs did not incite any toxicity attributes in comparison to controls at the tested concentrations.