Nanogenotoxicity is an emergent field, relevant for estimating the potential genotoxic risk of nanomaterials. In this study we investigated the genotoxic potential of zinc oxide (ZnO, ≤35 and 50 nm) and titanium dioxide (TiO 2 , 21 and 50 nm) nanoparticles (NPs) in the nuclei of Allium cepa root meristem cells by using a modified alkaline comet assay. ZnO and TiO 2 NPs were supplied to cells treated in vitro at 3 different concentrations (10, 100, and 1000 µg/mL). For the comet assay, our

more »

... s indicate a dose-dependent increment in DNA damage in cells exposed to 100 and 1000 µg/mL of ZnO NPs (≤35 and 50 nm) for percentage of DNA tail (% DNA tail). On the other hand, the results from TiO 2 NPs indicated that the DNA damage in the cells exposed to only the highest concentration (1000 µg/mL) of TiO 2 NPs (21 nm) is statistically significant in comparison to the control cells, while all concentrations of TiO 2 NPs (50 nm) are stat