Fig. 3. Cell survival measured on samples of MSSA with bare and functionalized P25TiO₂NPs after 6 h of irradiation. A: P25TiO₂NPs, B:vitaminB2@P25TiO₂NPs, C: vitaminC@P25TiO₂NPs in concentrations of 0.2 μg/mL (red) and 0.2 mg/mL (blue). p <0.05.

Since then, there has been a few animal studies suggesting titanium dioxide is connected to cancer. A 2017 study in Scientific Reports, for instance, found that rats with titanium dioxide in their diet had impaired immune systems, which could contribute to autoimmune diseases and colorectal cancer.

UV–vis spectra were carried out in the supernatant of both vitamins@P25TiO₂NPs samples after centrifugation to measure the amount of unbound vitamin. Standard curves at 375 nm and 255 nm were done for vitamin B2 and C, respectively, using a Synergy BioTeK multi-mode microplate reader.

JECFA previously assessed titanium dioxide at its 13^th meeting, at which time the expert committee assigned a “not specified” ADI for the additive due to an absence of significant absorption and a lack of toxicological effects in the available experimental animal and human studies. Since its original evaluation by JECFA, titanium dioxide has become a public point of contention, with its ban being introduced (and then subsequently withdrawn) in California legislation in 2023, a legal battle playing out in the EU over the additive’s ban and classification as a carcinogen in 2022, and the European Food Safety Authority (EFSA) calling titanium dioxide unsafe. However, supporters of titanium dioxide say that claims about its dangers are founded in unreliable studies, and some recent research has supported its safety as a food additive.