Do nanoparticles penetrate the skin?
According to Professor Tilman Butz who led the NANODERM project, the answer to is no, not in healthy human skin. The project looked at the dermal penetration of titanium dioxide nanoparticles and Butz concludes that as they don’t seem to cross the skin barrier they are safe to include in sunscreen products.
However, Butz offered a word of warning. The microscopic techniques the project used to follow the nanoparticles fate after application highlighted that sunscreens do not apply uniformly on the skin. At the microscopic level patches of the skin are left unprotected from harmful UV rays.
