This constant high rate of ROS production leads rapidly to extreme macromolecular oxidation, here it is observed in the AOPP and MDA detected after 3 h in samples treated with bare P25TiO₂NPs (Fig. 6, Fig. 7). Macromolecular oxidation includes, among others, both protein and lipid oxidation. The ROS causes protein oxidation by direct reaction or indirect reactions with secondary by-products of oxidative stress. Protein fragmentation or cross-linkages could be produced after the oxidation of amino acid side chains and protein backbones. These and later dityrosine-containing protein products formed during excessive production of oxidants are known as advanced oxidation protein products (AOPP). They absorb at 340 nm and are used to estimate the damage to structural cell amino acids. Lipid oxidation is detected by the conjugation of oxidized polyunsaturated lipids with thiobarbituric acid, forming a molecule that absorbs light at 532 nm. Polyunsaturated lipids are oxidized as a result of a free-radical-mediated chain of reactions. The most exposed targets are usually membrane lipids. The macromolecular damage could represent a deadly danger if it is too extensive, and this might be the case. Moreover, it could be observed that cellular damage continues further and becomes irrevocable after 6 h and MDA could not be detected. This may be due to the fact that the lipids were completely degraded and cells were no longer viable. Lipids from the cell membrane are the most prone to oxidation. In fact, lipid peroxidation biomarkers are used to screen the oxidative body balance [51]. At the same time, AOPP values are up to 30 times higher for bare nanoparticles in comparison to the functionalized ones.

There is some concern regarding skin and intestinal absorption of titanium dioxide nanoparticles, which are less than 100 nm in diameter.

According to Procurement Resource, the second half of the year would be passive for the price trendss of Titanium Dioxide. The major entities weighing on the prices are expected to be over-supply and matured inventories, sluggish demand from the downstream paints and varnishes, and enfeebled costs of upstream processes.