Physicochemical characterization and antioxidant properties of cerium oxide nanoparticles

Studies of the biological activity of cerium oxide nanoparticles (CONPs) show that this compound exhibits antioxidant, antitumor, antibacterial and antiviral properties. The CONPs were obtained by pulsed electron evaporation in a low-pressure gas with a specific surface area of ∼ 190 m 2 /g. Strongly-noequilibrium conditions of synthesis led to the formation of high defect structures, which makes it possible to change the Ce 3+ /Ce 4+ ions ratio and, consequently, to enhance the level of their biological activity. To analyze the content of cerium with different valences, X-ray photoelectron spectroscopy was performed. To determine the enzyme-like activity of CONPs, a chemical analysis of the interaction with hydrogen peroxide was carried out on a spectrophotometer. The results show a significant presence of Ce 3+ in CONPs and the inhibition of reactive oxygen species (ROS). The valence of the cerium atoms determines the chemical activity of CONPs; thus, in a more alkaline medium, the CONPs decrease the ROS concentration, while in the acidic medium its activity diminishes. By varying the parameters of the nanopowders obtained and achieving the optimum Ce 3+ /Ce 4+ ratio, one can produce CONPs having properties which enable the creation of pharmaceuticals for protection against ROS or for combating tumors, viruses and bacteria. © Published under licence by IOP Publishing Ltd.This work was performed within a support of the Russian Science Foundation project [16-16-04038]

Modifying the surface of cerium oxide nanopowders produced by physical method

Cerium oxide nanoparticles present an interesting material for different industrial applications in biotechnology and medicine. The CeO2 nanopowder was produced by the method of pulsed electron evaporation of ceramic oxide targets with condensation of the vapors in a low pressure gas. The modification of nanoparticle surface was made with sodium citrate and N-phosphonomethylaminodiacetic acid. The stable aqueous suspensions of CeO2 nanoparticles could not be obtained in the work. This is probably due to the high hydrophobic properties of the nanoparticle surface. The cerium oxide nanoparticles with different stabilizers exhibit luminescence properties. © 2019 Author(s)

Modifying the Surface of Cerium Oxide Nanopowders Produced by Physical Method

The work was supported by Russian Science Foundation project № 18-72-00041. The authors are grateful to A. N. Kiryakov (Ural Federal University) for assistance in luminescence measurements