A Study of Titanium Dioxide Nanoparticle Biokinetics via the Radiotracer Technique upon Intragastrical Administration to Laboratory Mammals

Abstract

A radiotracer technique is developed using titanium dioxide nanoparticles labeled by fast protons with the acquisition of a ⁴⁸V radioactive isotope, and the biokinetics of these brookite nanoparticles in the organisms of laboratory rats within the one-time intragastrical injection are studied. The main result of this work is the detection of titanium dioxide in the colon even within 5 days after injecting the slurry in an amount of 0.4% from the total exposition dose, which evidences the accumulation of titanium dioxide nanoparticles in the organ. This means that macro- and nano-fractions of titanium dioxide particles can be potentially dangerous for the colon, exerting a toxic and carcinogenic influence on its epithelial cells. Moreover, some traces of titanium dioxide nanoparticles are found to penetrate into the blood and liver. However, 98% of titanium dioxide is eliminated from the organism with feces within 5 days after injection. Neither kidneys nor brain exhibit the presence of titanium dioxide residues. This effect is due to the agglomeration of titanium dioxide nanoparticles, which is already significant and prompt in the solution for injection. At the same time, despite the ability of agglomerates to dissociate in the acidic medium of the stomach, only a few amounts of titanium dioxide pass into a nanometric form, which then penetrates through the colon into blood.