Zholobak Nm

UV-shielding property, photocatalytic activity and photocytotoxicity of ceria colloid solutions.

UV-shielding property, photocatalytic activity and cytotoxicity (including photocytotoxicity) of citrate-stabilized ceria colloid solutions were studied. It was established that UV-shielding property (namely, the sun protection factor, the critical absorption wavelength and the UVA/UVB-ratio) of ceria nanoparticles are as good as those of titanium dioxide and zinc oxide nanoparticles. It was further demonstrated that ceria nanoparticles possesses substantially lower photocatalytic activity, which additionally decreases upon decrease in ceria particle size. It was found that colloid ceria solutions are non-toxic to mouse fibroblasts (L929) and fibroblast-like cells of African Green monkey (VERO). Moreover, ceria nanoparticles are capable to protect these cells from UV-irradiation-induced damage. It was proposed that nanocrystalline ceria could be used not only as UV-blocking material, but also as prophylactic and even therapeutic compound for sunburns treatment.

Synthesis, cytotoxicity, antiviral activity and interferon inducing ability of 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines

New 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines were synthesized with high yields using bromoethylisatin and 6-(2-bromoethyl)-6H-indolo[2,3-b]quinoxaline as intermediates. These compounds were screened for the cytotoxicity, antiviral activity and interferon inducing ability. It was shown, that tested 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines are low toxic potent interferon inducers and antivirals. Morpholine and 4-methyl-piperidine derivatives appeared as the most active antivirals and the least cytotoxic in the investigated series.

Nanocrystalline ceria based materials—Perspectives for biomedical application

Nanocrystalline ceria possesses a unique complex of physical and chemical properties making it highly bioactive material. In this review, modern data on the action of nanocrystalline ceria on cells, micro- and macroorganisms are analyzed. Special attention is paid to the analysis of the factors affecting protective properties of CeO2 with respect to the living systems.

SYNTHESIS, DNA-BINDING, AND INTERFERON-INDUCING PROPERTIES OF ISATIN AND BENZOISATIN HYDRAZONES

The ability of isatin derivatives (in particular, aminoacetylhydrazones) to intercalate into DNA and to induce interferon secretion is demonstrated for the first time. The toxicity of isatin derivatives is much lower and its interferon inducing activity is somewhat lower as compared to the analogous benzoisatin derivatives. The DNA affinity of benzoisatin derivatives is two orders of magnitude greater than that of isatin derivatives.

Panthenol-stabilized cerium dioxide nanoparticles for cosmeceutic formulations against ROS-induced and UV-induced damage.

A method of panthenol-stabilized cerium dioxide nanoparticles synthesis was developed and their effect on the survival rate of human epidermoid cancer cells HEp-2 and diploid epithelial swine testicular cell line (ST-cells) under oxidative stress conditions induced by hydrogen peroxide introduction and UV irradiation was studied. The results obtained indicate that the use of panthenol as a stabilizer supposedly provides a substantial increase in the efficiency of protection. The degree of protection is determined by panthenol-to-ceria molar ratio. The combination of panthenol and nano-ceria protects biological objects under study from reactive oxygen species (ROS) and UV-irradiation more effectively than individual panthenol or ceria. The protective action of panthenol-stabilized cerium dioxide nanoparticles depends strongly on their composition and the means of their application.

Inactivation of the Nitroxyl Radical by Ceria Nanoparticles

43 Cerium dioxide CeO2 nanoparticles represent a promising object for biological applications [1], which is dictated by two key factors: their high oxygen non stoichiometry [2–4] and low toxicity [5, 6]. The former factor is responsible for activity of ceria nano particles in biochemical processes, in particular, in inactivation of free radicals in a living cell, while the latter one ensures relative safety of their use in vivo. Specific properties of CeO2 nanoparticles include the ability for regeneration, in particular, over a short period of time, the nanoparticles that have partici pated in a redox process return to their initial state (as regards oxygen nonstoichiometry) [7].

Advances and prospects of using nanocrystalline ceria in cancer theranostics

This review summarizes available information on the application of nanocrystalline ceria in cancer therapy and diagnostics (theranostics). Factors responsible for the high biological activity of nanocrystalline ceria are analyzed. Principles of design of multifunctional drugs based on CeO2 are considered, and examples of their practical use are presented.

Synthesis and antioxidant activity of biocompatible maltodextrin-stabilized aqueous sols of nanocrystalline ceria

A novel method is proposed for preparing biocompatible aqueous CeO2 sols, which allows purposefully adjusting particle sizes and biochemical properties of nanocrystalline ceria (NC). The usefulness of this method for preparing aqueous sols of Ce1 − xGdxO2 − x/2 solid solutions is demonstrated. Nanocrystalline ceria has been demonstrated to have a size-dependent activity in hydroxyl radical inactivation and in protecting mouse fibroblast cells (L929) from oxidative stress induced by hydrogen peroxide administration.

Direct monitoring of the interaction between ROS and cerium dioxide nanoparticles in living cells

A method for the direct monitoring of the interaction of reactive oxygen species (ROS) with cerium dioxide nanoparticles (CDN) in living cells is proposed based on the use of a complex of calcein and CDN. The CDN–calcein complex penetrates easily into a living cell and is decomposed readily by endogenous or exogenous ROS, releasing brightly fluorescent calcein, which can be observed using conventional fluorescent microscopy. This complex is less cytotoxic than individual cerium dioxide nanoparticles and provides effective protection from oxidative stress induced by the action of hydrogen peroxide, treatment with latex beads, or infection by the vesicular stomatitis virus.

Synthesis and biological activity of 7H-benzo[4,5]indolo[2,3-b]-quinoxaline derivatives.

New 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines (13-20) were synthesized with high yields starting from 3H-benzo[e]indole-1,2-dione. These compounds were screened for the cytotoxicity, anti-viral activity, interferon inducing ability and DNA affinity compared with the corresponding 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxaline derivatives (1-12). It was shown, that compounds 13-20 bind to DNA stronger (lg Кa=6.23-6.87) than compounds 1-12 (lg Кa=5.57-5.89). Anti-viral activity is significantly reduced with annulations of benzene ring in Indoloquinoxaline moiety 13-20.