Cytotoxicity of different sized TiO2 nanoparticles in mouse macrophages.

With large-scale production and wide application of nano-titanium oxide (TiO2), its health hazard has attracted extensive attention worldwide. In this study, mouse macrophages (Ana-1 and MH-S cells) were used to evaluate the cytotoxicity of different sized TiO2 nanoparticles. The results showed that TiO2 nanoparticles caused low toxicity, especially in MH-S cells. There was a difference in the cytotoxicity induced by different sized TiO2 particles. The 25 nm anatase particles induced the strongest cytotoxicity and oxidative stress, followed by 5 and 100 nm anatase particles; in contrast, 100 nm rutile particles induced the lowest toxicity. Although TiO2 nanoparticles induced high levels of intracellular reactive oxygen species (ROS), the determination of ROS demonstrated that the inherent oxidative capacity of TiO2 nanoparticles was lower in the absence of photoactivation. Therefore, the generation of intracellular ROS could not completely depend on inherent oxidative capacity of TiO2 nanoparticles. Toxicity of TiO2 nanoparticles could mainly depend on the structural characteristics.