ScienceDaily (Nov. 30, 2011) — Ultra-tiny zinc oxide (ZnO) particles with dimensions less than one-ten-millionth of a meter are among the ingredients list of some commercially available sunscreen products, raising concerns about whether the particles may be absorbed beneath the outer layer of skin. To help answer these safety questions, an international team of scientists from Australia and Switzerland have developed a way to optically test the concentration of ZnO nanoparticles at different skin depths. They found that the nanoparticles did not penetrate beneath the outermost layer of cells when applied to patches of excised skin.
The results, which were published this month in the Optical Society’s (OSA) open-access journalBiomedical Optics Express, lay the groundwork for future studies in live patients.
