Comparison of cytotoxic effects of different sizes and shapes of SiO2 nanoparticles on rat lung cells

Silica nanoparticles could enter the living animals and humans through inhalation، ingestion، injection and skin، exerting potentially adverse effects on health and environment. The aim of this experimental laboratory study was to evaluate toxicities of silica nanoparticles in the form of wire، rod and sphere with different sizes (20، 50 and 100 nm) on rat pulmonary cells after 6 and 24 hours of exposure، using from 3- (4،5-Dimethylthiazol-2-y1) -2،5diphenyltetrazolium bromide (MTT) and 3- (4،5-dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl) -2- (4-sulfophenyl) -tetrazolium (MTS) cytotoxicity tests.

Two male Wistar rats were anesthetized، their blood was completely replaced with Crebs solution، and their lungs removed to be digested for preparation of single cell suspensions in medium culture. Cell suspensions were separately treated with the above-mentioned nanoparticles at concentration of 500 µg/mL and 37 ºC incubation، and cell viability was assessed after 6 and 24 hours.

This study showed that smaller (20 nm) nanoparticles had more cytotoxic properties than larger ones. Also، spherical nanoparticles induced more cytotoxicity compared with other forms. Longer (24 hours vs. 6 hours) exposure resulted in slightly more cell death.

Cytotoxicity of nanoparticles depends on their shape، size and exposure duration.