TiO particles induce ER stress and apoptosis in human hepatoma cells, HepG2, in a particle size-dependent manner.

The cytotoxicity of TiO nanoparticles are well-known, but the particle size-dependent induction of ER stress and apoptosis by TiO in hepatocytes has not been elucidated clearly. In the present study, we investigated whether a fine TiO particle and two types of TiO nanoparticles induce ER stress and apoptosis differently in HepG2 cells. A particle size-dependent decrease in cell viability was observed after exposure to the TiO particles.