Permeability of skin to silver nanoparticles after epidermal skin barrier disruption in rats

Abstract

— 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) percutaneous-ly for 24 hr after disruption of the epidermal barrier by tape stripping (TS) or acetone wiping (AC). Sys-temic toxicity was examined hematologically and histopathologically, and by assessing blood biochemis-try. 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 abnor-mal histopathological changes in the liver were observed in all rats. In the blood, silver was below detect-able levels in all rats and had no adverse effects on hematology or blood biochemistry. These results indi-cate 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.