The results of modern studies of physicochemical properties and biological activities of nanocrystalline cerium dioxide are generalized. The key methods for its preparation are considered and the prospects for its application in biological research and in medicine are analyzed.

Предложены новые методы получения водных золей нанокристаллического диоксида церия, стабилизированных лимонной и полиакриловой кислотами. Методами просвечивающей электронной микроскопии и УФ-видимой спектроскопии исследована устойчивость золей к гидротермальной обработке в диапазоне температур 120–210°С.

New methods are proposed for preparing aqueous sols of nanocrystalline ceria stabilized by citric or polyacrylic acid. Transmission electron microscopy and UV-Vis spectroscopy were used to study the stability of sols in hydrothermal treatment at temperatures in the range of 120–210°C.

AIM:To synthesize a conjugate of hematoporphyrin with gold nanoparticles, and to evaluate its photodynamic activity in experiments on cultures of transformed cells.METHODS:nanosized gold particles and nanocomposites synthesis methods, cell culture methods, photobiology methods, trypan blue dye exclusion test, chemiluminescence assay.RESULTS:Various hematoporphyrin-gold nanocomposites were obtained, which contained similar hematoporphyrin concentration (5 microg/ml) and varied concentrations (0.5-5 microg/ml) of gold nanoparticles with a diameter of 15 nm or 45 nm. It was established by chemiluminescence method that nanocomposites synthesized induce more efficiently the formation of photo-oxidative products than original photosensitizer. The experiments with transformed cell lines showed that photodynamic in vitro activity of synthesized hematoporphyrin-nanogold composites is much higher than that of the original photosensitizer. The better activity of the nanocomposites with gold particles of 45 nm vs such of 15 nm which was demonstrated in the experiments, can be apparently connected with the fact that bigger particles are able to transport more porphyrin molecules into malignant cells.CONCLUSION:The results obtained warrant the necessity of further studies with hematoporphyrin-gold nanocomposites in vivo on transplanted tumors of animals which have to define the real perspectives of the nanocomposites application in PDT.

Antiviral activity of nanosize cerium dioxide sols (CeO2) in animal cell culture has been studied. The inhibiting effect of the mentioned sols upon reproduction of vesicular stomatitis test-virus was demonstrated for the first time in case of preliminary 24-hour contact with cells lines L929 and EPT. The effectiveness of protective action depends on initial precursor and the way of obtained water nanosize nanosols.

We study the ability of ceria nanoparticles to inhibit the oxidative degradation of anthocyanins. CeO 2 nanoparticles stabilized by sodium polyacrylate or sodium citrate can substantially slow down the oxidation of anthocyanins of grapes caused by hydrogen peroxide at pH ≥ 7.0. In acid solutions, inhibition is not observed.