Bioaccumulation of silver and gold nanoparticles in organs and tissues of rats studied by neutron activation analysis

Bioaccumulation of silver (Ag) and gold (Au) nanoparticles (NPs) with mean sizes of 35 nm and 6 nm, respectively, has been studied after their intragastric administration to rats at a dose of 100 mu g/kg of body weight for 28 or 14 days. The organs and tissues (liver, kidney, spleen, heart, gonads, brain, and blood) were subjected to thermal neutron activation, and, then, the activity of the Ag-110m and Au-198 isotopes generated was measured. The NPs of both metals were detected in all biological samples studied, the highest specific weight and content of Ag NP being found in the liver, and those of Au being found in kidneys of animals. The content of Ag NPs detected in the brain was 66.4 +/- 5.6 ng (36 ng/g tissue), no more than 7% of these NPs being localized in the lumen of brain blood vessels. The content of Ag and Au NPs found in organs and tissues of rats could be regarded as nonhazardous (nontoxic) in accordance with the known literature data.