Cytotoxicity and mitochondrial damage caused by silica nanoparticles

► Cytotoxicity and mitochondrial damage caused by silica nanoparticles were investigated. ► HepG2 cells were treated with different concentrations of silica nanoparticles for 3 and 24 h. ► Intracellular ROS, mitochondrial membrane potential, apoptosis were detected. ► Mitochondrion was the major organelle for the cytotoxicity of silica nanoparticles.