On the other hand, titanium dioxide is a synthetic mineral that is produced through a chemical reaction involving the mineral ilmenite or rutile. It is used in industries such as cosmetics, paint, and sunscreen as a whitening agent and pigment. The manufacturing process of titanium dioxide involves extracting the mineral from ores, purifying it through chemical processes, and then grinding it into a fine powder.

Our scientific experts applied for the first time the 2018 EFSA Scientific Committee Guidance on Nanotechnology to the safety assessment of food additives. Titanium dioxide E 171 contains at most 50% of particles in the nano range (i.e. less than 100 nanometres) to which consumers may be exposed.  

In order to contribute with experimental evidence that could help to achieve a better understanding of the field for future regulation, in the present work, the biocompatibility of commercial P25TiO₂NPs (one type of TiO₂NPs used in sunscreen formulations) and two novel functionalized P25TiO₂NPs were evaluated under solar simulated irradiation. White light, generated by red, blue, and yellow LEDs, together with UV ones, was chosen to simulate the solar spectra. Functionalization of TiO₂NPs was made with antioxidant vitamins in order to prevent the expected photo-initiated ROS production when nanoparticles are exposed to the simulated solar spectra. Vitamin B2 (riboflavin) and vitamin C were chosen to carry out the functionalization because they are water-soluble, low-cost, and are a constitutive part of biological processes. In addition, it is known that both have the potential to prevent macromolecular oxidation by ROS [23], [24], [25], [26].