A study of the effects of citrate-coated silver nanoparticles on RAW 264.7 cells using a toolbox of cytotoxic endpoints

Citrate-coated silver nanoparticles (citrate-AgNPs) are among the most commonly used nanomaterials, widely present in industrial and biomedical products. In this study, the cytotoxicity of 30-nm citrate-AgNPs on the macrophage cell line RAW 264.7 was evaluated, using a battery of cytotoxicity endpoints (viability, oxidative stress, and cytostaticity/clastogenicity), at 24 and 48 h of exposure. Citrate-AgNPs decreased cell proliferation and viability only at 75 mu g/mL, suggesting a low sensitivity of RAW cells to lower doses of these AgNPs. After 24 h of exposure, ROS content decreased in cells exposed to 60 mu g/mL AgNPs (IC20 value), corroborating the high tolerance of these cells to citrateAgNPs. However, these cells suffered an impairment of the cell cycle, shown by an increase at the sub-G1 phase. This increase of the sub-G1 population was correlated with an increase of DNA fragmentation, suggesting an increase of apoptosis. Thus, our data are important to understand the effects of low concentrations (IC20) of citrate-AgNPs on in vitro vital macrophage functions.