text: The results demonstrated that four TiO2 nanoparticles had low toxicity in Ana-1 cells (<30% decrease in cell viability at 600 mg/ml), which was similar to the toxicity of 5 nm anatase particles in L929 cells (Jin et al., 2008) and 15 nm anatase particles in glomerular mesangial (IP15) cells (L’Azou et al.