the toxic effects of silver nanoparticles on blood mononuclear cells

background: nanoparticles have become one of the leading technologies over the past two years. the extensive use of nanoparticles has raised great concern about their occupational fate and biological effects. with an increase in the production and use of nanomaterial, it is more likely to get exposed to them occupationally and environmentally. objective: to assess the toxicity of silver nanoparticles on human mononuclear cells. methods: in this in vitro experimental study, suspensions of blood mononuclear cells from 10 young healthy men were incubated with 10-nm silver nanoparticles in different concentrations (range: 1–500 μg/ml) for 6 and 24 hours by mtt assay. positive and negative controls were used for comparison. results: after 6 hours of exposure, 10.9% to 48.4% of the cells died. after 24 hours of exposure, the rate ranged from 56.8% to 86.3%. regardless of the exposure time, the maximum cytotoxicity was observed at the concentration of 500 μg/ml of silver nanoparticles. by increasing the exposure time to 24 hours, the cytotoxicity of nanoparticles substantially increased at all concentrations. cell death was significantly higher when compared to the controls (p<0.01). conclusion: silver nanoparticles possess both time- and dose-dependent cytotoxicity and can thus be considered as very toxic for mononuclear cells.