In addition to its pharmaceutical applications, barium sulphate is extensively utilized in the production of paints and coatings, where a bright white pigment is essential. The opacity and brightness provided by barium sulphate make it a popular choice in formulations for white and colored paints. Its non-toxic nature and excellent stability enhance its appeal in these products.

As mentioned above, these oxide NPs are harmful in part because both anatase and rutile forms are semiconductors and produce ROS. Particularly, P25 kind has band-gap energies estimated of 3.2 and 3.0 eV, equivalent to radiation wavelengths of approximately 388 and 414 nm, respectively. Irradiation at these wavelengths or below produces a separation of charge, resulting in a hole in the valence band and a free electron in the conduction band, due to the electron movement from the valence to conduction bands. These hole–electron pairs generate ROS when they interact with H₂O or O₂ [43,44]. It was described that they can cause an increase in ROS levels after exposure to UV-visible light [45]. The NBT assay in the studied samples showed that bare P25TiO₂NPs produce a large amount of ROS, which is drastically reduced by functionalization with vitamin B2 (Fig. 5). This vitamin, also known as riboflavin, was discovered in 1872 as a yellow fluorescent pigment, [46] but its function as an essential vitamin for humans was established more than sixty years later, and its antioxidant capacity was not studied until the end of the XX century [47,48]. This antioxidant role in cells is partially explained because the glutathione reductase enzyme (GR) requires it for good functionality. This enzyme is the one in charge of the conversion of oxidized glutathione to its reduced form which acts as a powerful inner antioxidant and can quench the ROS [49,50]. The cost of this action is that the glutathione is converted to the oxidized form and needs to be recovered by the GR. Consequently, the cells need more vitamin B2. Another glutathione action is the protection against hydroperoxide. This activity is also mediated by riboflavin. Therefore, local delivery of this vitamin seems to significantly help the cells in their fight to keep the oxidative balance, once they are exposed to high levels of ROS.

Plus, titanium dioxide is chemically inert, meaning it won't react with other substances in the paint. This stability ensures that the paint retains its original color and properties over time, preventing discolouration and degradation. Using titanium dioxide as an ingredient, the paint can withstand harsh weather conditions and prevent flaking, peeling or chalking. This exceptional durability makes it ideal for interior and exterior walls, ensuring a long-lasting and beautiful finish.

Background

Of the products that include the additive in their labels, Thea Bourianne, senior manager at data consultant Label Insights, told Food Navigator USA in May 2021 that more than 11,000 products in the company's database of U.S. food and beverage products listed titanium dioxide as an ingredient. Non-chocolate candy led those numbers at 32%. Cupcakes and snack cakes made up 14%, followed by cookies at 8%, coated pretzels and trail mix at 7%, baking decorations at 6%, gum and mints at 4% and ice cream at 2%.