Abstract:

Abstract:Objective To detect the cell uptake and intracellular distribution of silica nanoparticles in HepG2 cells after treated with silica nanoparticles and the cytotoxicity of HepG2 cells caused by the particles and discuss the relationship between intracellular distribution of nanoparticles and cytotoxicity.
Methods The size,shape and dispersibility of silica nanoparticles were detected by transmission electron microscope (TEM) and dynamic light scattering method. The cell uptake and intracellular distribution of silica nanoparticles were observed by fluorescence microscope and TEM. The HepG2 cells were exposed to different concentrations (0,25,50,100 and 200 mg·L-1) of silica nanoparticles for 24 h, the cell viability was reflected by MTT assay and the changes of mitochondrial membrane potential (MMP) were measured by flow cytometry. Results The TEM results  showed that silica nanoparticles were spherical and well dispersed. The dynamic light scattering method results manifested that the size of silica nanoparticles in serum-free DMEM was about 94 nm and well dispersed. Silica nanoparticles could enter into the cells after HepG2 cells were treated with the particles for 3 h. After 24 h treatment,silica nanoparticles were found to disperse in cytoplasm with single particle or cluster form. The particles coulddeposit in some organelles such as mitochondria. After the HepG2 cells were exposed to different concentrations of silica nanoparticles for 24 h,the cell viabiliyand MMP in treated groups were decreased significantly (P＜0.05) in a dose-dependent manner. Conclusion The silica nanoparticles can damage the organelles which is one of the mechanisms of cytotoxicity induced by silica nanoparticles.

Key words: silica nanoparticles；intracellular distribution；mitochondria；cytotoxicity