Spectral Behaviour of Nanosized Materials Nanotubes/Cerium Oxide for UV Protection of Skin

Abstract

The nanomaterials developed by the authors were characterized in the optical absorption range with a focus on the UV range. Halloysite nanotubes (HNTs) and cerium oxide (CeO₂) have specific spectral absorption that has cumulative effect. The UV absorption of the HNTs@CeO₂ composites exhibited maxima at 269–305 nm, with a much higher absorption intensity and a wider band than the original HNTs. A blue shift of the UV absorption band was observed for the small CeO₂ particles, and the shift was found to be nonlinearly related to the particle size. The nanoparticle sizes were within 1–15 nm. With electron microscopy it was shown that the CeO₂ particles were evenly distributed on the HNTs, resulting in low particle agglomeration. The creams showed effective protection against UV radiation and had additional healing properties, which were confirmed on the skin of guinea pigs.