Pre-irradiation of anatase TiO2 particles with UV enhances their cytotoxic and genotoxic potential in human hepatoma HepG2 cells

► The photocatalytic properties of TiO2 are exploited in numerous applications. ► The potential toxicity of photo-activated (UV pre-irradiated) TiO2 is unknown. ► We studied toxicity of non-irradiated and UV pre-irradiated anatase TiO2 particles. ► UV pre-irradiated (photo-activated) TiO2 particles show higher toxic potential. ► These findings are important for evaluating human and environmental risk assessment.