Cell Membrane Injury Induced by Silica Nanoparticles in Mouse Macrophage

Studies on the cytotoxic mechanism of SiO₂ nanoparticles is of vital importance for estimating the potential risk of overexposure and cytotoxicity amelioration and safety precautions of SiO₂ nanoparticles. The cell membrane injury induced by 20-nm silica nanoparticles was investigated by measuring reactive oxygen species (ROS), membrane fluidity and free Ca²⁺ content ([Ca²⁺]_i) in cells with laser scanning confocal microscope (LSCM). The 20-nm SiO² nanoparticles at different concentrations of 31.25, 125, and 500 g/ml were respectively incubated with RAW264.7 cells for 24 h to determine oxidative stress responses, membrane fluidity, intracellular [Ca²⁺]_i concentration. Exposure to SiO₂ nanoparticles at 125 and 500 g/ml increased ROS levels and intracellular [Ca²⁺]_i, reduced membrane fluidity levels. The decrease of the membrane fluidity indicated membrane damage. Increases of ROS generation and intracellular [Ca²⁺]_i played a role in cytotoxicity. Results showed that mechanisms of cytotoxicity induced by SiO² nanoparticles was closely correlated to increase oxidative stress, decrease membrane fluidity and perturbation of intracellular calcium homeostasis.