Size-dependent acute toxicity of silver nanoparticles in mice.

In this study, we aimed to evaluate changes in the acute toxicity of intraperitoneally administered silver nanoparticles (AgNPs) of varying sizes in BALB/c mice. Seven-week-old female BALB/c mice were intraperitoneally administered AgNPs measuring 10, 60, or 100 nm in diameter (0.2 mg/mouse) and then sacrificed 1, 3, or 6 h after treatment. In mice administered 10 nm AgNPs, reduced activity and piloerection were observed at 5 h post administration, and lowered body temperature was observed at 6 h post administration, with histopathological changes of congestion, vacuolation, single cell necrosis, and focal necrosis in the liver; congestion in the spleen; and apoptosis in the thymus cortex. These histopathological changes were not evident following administration of either 60 or 100 nm AgNPs. These results suggested that smaller AgNPs, e.g., those measuring 10 nm in diameter, had higher acute toxicity in mice.