Toxicity and Biokinetics of Colloidal Gold Nanoparticles

Gold nanoparticles (Au-NPs) have promising potential for diverse biological application, but it has not been completely determined whether Au-NP has potential toxicity in vitro and in vivo. In the present study, toxicity of Au-NP was evaluated in human intestinal cells as well as in rats after 14-day repeated oral administration. Biokinetic study was also performed to assess oral absorption and tissue distribution. The results demonstrated that Au-NP did not cause cytotoxic effects on cells after 24 h exposure in terms of inhibition of cell proliferation, membrane damage, and oxidative stress. However, when a small number of cells were exposed to Au-NP for seven days, colony forming ability remarkably decreased by Au-NP treatment, suggesting its potential toxicity after long-term exposure at high concentration. Biokinetic study revealed that Au-NP slowly entered the blood stream and slightly accumulated only in kidney after oral administration to rats. Whereas, orally administered Au ions were rapidly absorbed, and then distributed in kidney, liver, lung, and spleen at high levels, suggesting that the biological fate of Au-NP is primarily in nanoparticulate form, not in ionic Au. Fourteen-day repeated oral toxicity evaluation showed that Au-NP did not cause severe toxicity in rats based on histopathological, hematological, and serum biochemical analysis.