In Vitro Toxicity Evaluation of 25-nm Anatase TiO 2 Nanoparticles in Immortalized Keratinocyte Cells

Titanium dioxide (TiO 2 ) nanoparticles (NPs) are massively fabricated and widely used in daily life, and thus potential risk has been posed to human health. However, the mechanism of the interaction between TiO 2 NPs and cells is still unclear. In this study, the interaction of anatase TiO 2 NPs with HaCaT cells is studied in vitro with multi-techniques. The TiO 2 NPs not only insert into cells through endocytic pathway but also penetrate into the cell. The TiO 2 NPs could produce reactive oxygen species (ROS) after dispersion spontaneously. Furthermore, the interaction between TiO 2 NPs and cellular components might also generate ROS. The ROS generation could lead to cellular toxicity if the level of ROS production overwhelms the antioxidant defense. Cytoskeletal components, particularly the microfilaments and microtubules, cause modifications upon exposure to TiO 2 NPs. With all results, the toxicological effects of TiO 2 NPs on HaCaT cell can be simplified into six events.