Titanium Dioxide Nanoparticles in sunscreens and skin photo-damage. Development, synthesis and characterization of a novel biocompatible alternative based on their in vitro and in vivo study

Titanium dioxide nanoparticles are widely used in cosmetics, especially in sunscreens due to their capacity to absorb UV harmful wavelengths. However, their biocompatibility remains controversial. In this work, the effect of titanium dioxide nanoparticles, particularly Degussa P25 (P25TiO₂NPs) under solar-simulated radiation was studied in vitro and in vivo. Cell viability and tissue integrity were affected after exposure to P25TiO₂NPs and light for 6 h, showing signs of significant oxidative stress markers and reduced tissue integrity observed by TEM. In order to avoid these undesired effects, a novel biocompatible alternative was presented based on titanium dioxide nanoparticle functionalization with vitamin B2 through a rapid sol-gel method. None of the phototoxicity effects were observed with these functionalized nanoparticles.