Effect of Cerium Compounds on Post-Burn Scar Studied in vivo by Transmission Electron Microscopy

The effect of nanosized cerium dioxide and a solution of cerium (III) chloride on the state of a post-burn scar was studied in an in vivo experiment via transmission electron microscopy. The intracellular accumulation of cerium compounds with their agglomeration with cytoplasmic and/ or lysosomal localization was observed after 4 injections of nanodispersed cerium dioxide or cerium (III) chloride solution at concentrations of 0.5% and 0.05% in the formed scar area. The application of the cerium preparations both in nanodisperse form (sol) and in solution did not cause inflammatory reactions or cell destruction and had a positive effect on a regenerative process; it contributed to the full-fledged tissue regeneration in a shorter time and changed the scar characteristics for the better. sol, nanodispersed cerium dioxide, cerium (III) chloride solution, electron microscopy, post-burn scar, functional activity of cells

Cerium Oxide Nanoparticles Affect Heavy Metals Uptake by Pea in a Divergent Way than Their Ionic and Bulk Counterparts

The impact of cerium oxide nanoparticles, bulk cerium oxide and ionic cerium nitrate on the plant development as well as the uptake and further translocation of Cu, Mn, Zn and Fe by sugar pea (Pisum sativum L.) was investigated. Plants were cultivated in the laboratory pot experiments using the modified Hoagland solutions supplemented with cerium compounds at the 200 mg L−1 Ce level. Analysis of variance proved that cerium oxide nanoparticles significantly decreased Cu, Mn, Zn and Fe concentrations in roots and above ground parts of the pea plants. The latter ions are presumably transported via symplastic pathways and may compete with nanoparticles for similar carriers. The lowest impact on the plant growth and the metal uptake was observed under the bulk CeO2 treatment. On the contrary, strongest interactions were observed for supplementation with ionic cerium nitrate. The highly beneficial effect of cerium oxide nanoparticles on the plant growth was not supported by this study. The latter conclusion is of particular relevance when environmental impact of cerium compounds on the waste management, municipal urban low emissions and food production is to be concerned.

Characteristics of the response of the microalga (Dunaliella viridis) to cerium compounds in culture

Recently, nanobiotechnology has been developing intensively; therefore, various properties of nanoparticles, which depend on their origin, concentration, and size, are of interest. It is known that CeO2 nanoparticles cause a positive biological effect. These particles are able to penetrate through biomembranes. At the same time, there are assumptions about a high degree of biological risks when using nanomaterials, and it is obvious that the biosafety of nanomaterials is decisive in the development of new products, including for medicine. The cytotoxicity of samples of cerium salts and cerium dioxide nanoparticles of different sizes was assessed at different concentrations using D. viridis. The cytotoxicity level by morphological and functional disorders of D. viridis was investigated, as determined by the change in cell shape, accumulation of inclusions, loss of flagellum, change in nature and movement, the formation of micro- and macroaggregates by D. viridis cells and exometabolite release. The cytotoxicity coefficient was calculated as a quotient of total detected changes divided by their number. It was shown that cerium salts (cerium (IV) ammonium nitrate and cerium (III) chloride) had pronounced cytotoxicity, which exceeded cytotoxicity values of the control by 7 and 6 times, respectively. Cerium dioxide nanoparticles with a size of 6 nm at a concentration of 0.01 M showed intermediate cytotoxicity, which exceeded control values by 3.5 times, and after the effect of nanoparticles with a size of 2 nm at a concentration of 0.1 M, the cytotoxicity coefficient corresponded to control values. The addition of inactivated blood serum to the incubation mixture resulted in a decreased cytotoxic effect of cerium dioxide. The use of D. viridis as a test system will supplement the arsenal of biotesting tools for nanomaterials and the study of the mechanisms of their effect.