Propriedades fotoprotetoras de bionanocompósitos de alginato de sódio contendo ZnO, TiO2 e CeO2

Abstract

Ultraviolet radiation (UV) is a specific region of sunlight that affects the skin and its waveband is classified into UVA, UVB and UVC regions. The penetration of radiation into the skin occurs unevenly, and although the skin has natural systems that help in protection, it is not fully effective in combating the damage caused by solar radiation, which can lead to skin cancer. Thus, there was a need to use substances capable of preventing skin burns from sunlight. Sunscreens can act in two ways to prevent radiation penetration into the skin, absorbing or scattering radiation of one or more wavelengths. The cosmetic industries use oxides such as ZnO and TiO2 and CeO2, but these oxides are of limited use. Aiming at a material with greater sensorial quality, a new technology of inorganic filters was generated, the nanoparticulate version, even so these oxides are difficult for a cosmetic formulation, since most of them result in agglomerates generating the formation of a non-homogeneous film and of 3ow level of protection, in addition to poor aesthetics. In order to minimize the problems caused by nanoparticles and make them more stable and homogeneous, this work aims to obtain nanocomposites formed by inorganic nanoparticles and the sodium alginate biopolymer. Nanometric ZnO, CeO2 and TiO2 oxides were synthesized using Sol-Gel methodology, and the nanocomposites were prepared using In Situ and dispersion methodologies. XRD analysis together with Raman spectroscopy confirmed the formation of zinc and cerium oxides, and the formation of titanium oxide in the rutile phase, while SEM analysis confirmed the formation of nanoparticles. UV-Vis Absorption Spectroscopy confirmed that the samples have absorption between 250 and 400 nm, characteristic wavelengths of UVA and UVB radiation. With this, we can verify that the methodologies were efficient for the formation of oxides and nanocomposites, and that the materials absorb ultraviolet radiation, which makes the materials suitable to be used as sunscreens.