The cytotoxic effect was tested through the colorimetric assay employing 3′-[1-[(phenylamino) -carbonyl]−3,4-tetrazolium]-bis(4‑methoxy-6-nitro) benzene-sulfonic acid hydrate (XTT) by reading the absorbance at 490 nm after 3 h of incubation post treatment [28]. The absorbance is proportional to the metabolic rate of viable (live) cells.
The most significant uncertainty identified by the EU experts was the concern that TiO2 particles may have genotoxic effects. Genotoxicity refers to the ability of a chemical to directly damage genetic material within a cell (DNA), which may lead to cancer in certain situations. Although the experts did not conclude that TiO2 particles in E171 are genotoxic, they could not rule out the concern that they might be.
Moreover, lithopone suppliers are expanding their product lines to offer variations of the pigment that meet specific market needs. Some suppliers provide specialized grades of lithopone that are tailored for particular applications, such as high gloss paints or specialty coatings. By offering these tailored solutions, suppliers can help paint manufacturers enhance the performance characteristics of their products, thus gaining a competitive edge in the market.