- Makiko Kuwagata (Hatano Research Institute Food and Drug Safety Center / email@example.com)
1) Hatano Research Institute Food and Drug Safety Center , 2) Laboratory of Toxicology and Safety Science Graduate School of Pharmaceutical Science Osaka University , 3) Vaccine Creation Project, BIKEN Innovative Vaccine Research Alliance Laboratories, Research Institute for Microbial Diseases, Osaka University
To analyze the permeability of rat skin to silver nanoparticles, the dorsal skin of Sprague-Dawley rats was exposed to 5 nm Ag nanoparticles or silver nitrate (Ag+ ions) percutaneously for 24 hr after disruption of the epidermal barrier by tape stripping (TS) or acetone wiping (AC). Systemic toxicity was examined hematologically and histopathologically, and by assessing blood biochemistry. Although parakeratosis, decrease in keratohyaline granule, and thickening in the epidermis occurred following exposure to both 5 nm Ag nanoparticles and Ag+ ions after TS or AC, no Ag-specific changes were observed. Inductively coupled plasma mass spectrometry (ICP-MS) showed silver in the skin of rats exposed to both 5 nm Ag nanoparticles and Ag+ ions after TS or AC. Silver was only detected in the liver of rats exposed to Ag+ ions after TS, but not exposed to 5 nm Ag nanoparticles after TS or AC. No abnormal histopathological changes in the liver were observed in all rats. In the blood, silver was below detectable levels in all rats and had no adverse effects on hematology or blood biochemistry. These results indicate that silver ions released from 5 nm Ag nanoparticles can percutaneously infiltrate the body only when the skin barrier is disrupted, but does not induce any acute toxicity.