Comparative toxicity assessment of nano- and bulk-phase titanium dioxide particles on the human mammary gland in vitro.

There is a major concern that exposure to titanium dioxide (TiO) nanoparticles (NPs) can have degrading effects on human health as well as mammary gland because of the increased use in numerous sorts of nanotech-based health care and food merchandise. Also, there is a scarcity in NP toxicity studies on the mammary gland; therefore, the aim of the present study was to compare toxicity caused by nano- and bulk-phase TiO particles on the human mammary gland in vitro. In comparison to bulk-TiO particles, nano-TiO cause a significant ( < 0.05) reduction in viability and increased reactive oxygen species generation in the human mammary epithelial cells after a dose- (1, 2, 5, 10, 20, 50, and 100 µg/mL) and time (6, 12, 24, and 48 h)-dependent exposure. Further, an increase in genotoxicity in the mammary epithelial cells was observed as percent tail DNA and comet area was increased significantly ( < 0.05) at 12 h of exposure (10 and 100 µg/mL) with nano-TiO. The scanning electron microscopic examination showed that a 50 µg/mL dose of both nano-TiO and bulk-TiO particles cause morphological changes and retarded growth pattern of mammary epithelial cells at 12 h. Moreover, a significant ( < 0.05) increase in apoptosis at 10 µg/mL and necrosis at 50 µg/mL concentrations of nano-TiO in comparison to bulk-TiO was observed in mammary epithelial cells. Finally, we can conclude that the toxicity caused by nano-TiO particles on the human mammary gland cells was comparatively higher than the bulk-TiO particles.