Toxicity of silver nanoparticles in mouse bone marrow-derived dendritic cells: Implications for phenotype.

Silver nanoparticles (AgNP) are one of the most studied nanoparticles due to their anti-bacterial, -fungal, -viral, -parasitic, and -inflammatory properties. This raises the need to evaluate the toxicity and biological effects of AgNP in the immune system in order to develop new safer biomedical products. In this study, an AgNP formulation currently approved for veterinary applications was applied to mouse bone marrow-derived dendritic cells (BMDC), considered important antigen-presenting cells of the immune system, to evaluate cytotoxicity, genotoxicity, and any significant influence on expression of cellular markers associated with BMDC phenotype and maturation status. The results showed that after 12 h of AgNP exposure, a significant decrease in BMDC viability occurred at the highest concentration tested (1.0 µg AgNP/ml) and at lower doses, the cells maintained membrane integrity and metabolic activity. DNA damage was not significant with any AgNP level aside from the 1.0 µg AgNP/ml level. Regarding phenotype, no differences in expression of CD40 (co-stimulatory molecule highly present in mature BMDC) or in CD273 (a marker for inhibitory T-cell response) were observed. The current results showed that the toxicity of this AgNP formulation was dose-related. The findings also suggest BMDC could maintain structural conservation of co-stimulatory/co-inhibitory surface molecules after 12 h of exposure to this AgNP. This work represents the first step in identifying the toxic effects of this AgNP formulation on dendritic cells.