New Generation Inorganic Nanoparticles for Sunscreen UV Filtration

Australia has one of the highest melanoma rates worldwide owing to extremely high ultraviolet (UV) levels due to ozone depletion. Thus, effective protection against UV radiation is a necessity. Sunscreens contain titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles as inorganic UV filters to protect the skin from damaging UV light by means of scattering, absorption and reflection. However, these nanomaterials have the potential to penetrate the skin and impart cytotoxicity on viable cells caused by free radicals generated as a result of their photocatalytic activity. As such, health concerns have been raised regarding their use in cosmetic products. Toxicological reviews of these particles have reported inconclusive results due to the differences in test protocols and lack of real-life conditions, including the absence of UV irradiation. Regardless of these discrepancies, the photocatalytic activity of these materials is a key property that should be reduced to avoid potential detrimental effects, not only to humans but also to the environment.