This cytotoxic effect was also reported before; i.e. Natarajan et al. conducted an experiment that found a strong oxidative stress, morphological changes in mitochondria and substantial loss in the fusion of primary hepatocytes exposed to P25TiO2NPs [52].
It turns into light gray after being exposed to ultraviolet rays in sunlight for 6 to 7 hours, but it will return to its original color when placed in a dark place. It is easy to oxidize in the air and then agglomerate and deteriorate when exposed to moisture.