In Vivo Subacute Oral Toxicity Assessment of Multiwalled Carbon Nanotubes: Characteristic of Nanomaterial and Integral Indicators

Abstract

Carbon nanotubes are produced on a large scale by the nanotechnology industry. Oral exposure scenario of human is possible with a CNTs migration into food of the most promising composite packaging materials, systems for water treatment, agriculture—when used as a plant growth stimulant, carriers for agricultural chemicals and others. Objective: development of a method of oral administration CNTs to laboratory rats, allowing the use in subacute or chronic toxicological experiment of at least 3 months and assessment of the effect of CNTs on the integral and physiological parameters of the animal organism. The object of research is the multiwalled CNTs “Taunit-M®” with the outer diameter of the particles—15–40 nm, the diameter of the inner cavity—3–8 nm, the average length—2 μm. MWCNTs were given to male Wistar rats daily in doses from 0.01 to 10 mg/kg body weight during 100 days. MWCNTs were prepared with drinking liquid in the form of aqueous dispersions, stabilized with the surface-active substance (SAS) Tween-20. During the experiment, as well as after its finishing in the animals were determined integral indicators, the level of anxiety and cognitive function using the test “passive avoidance response,” and amount of macromolecules absorbing in the gut. Results. There was a significant decrease in the mass of thymus at 26–35% over the entire range of doses of MWCNTs, an increase of brain and adrenal mass. Absorbability of the protein antigen in the gut of animals receiving the only surfactant was greater than that of animals receiving MWCNT’s. Some of these changes were observed at a dose of 0.01 MWCNT’s mg/kg body weight.