Vol 13, No 5-6 (2018)

In this work, a novel approach to magnetic nanotheranostics based on the activation of magnetic nanoparticles (MNPs) with a nonheating low-frequency magnetic field has been described. Electromagnetic biomedical technologies implemented in low-frequency nonheating and radiofrequency heating magnetic fields have been briefly reviewed and compared. It has been shown that the activation of MNPs with nonheating magnetic fields has several advantages over activation with heating magnetic fields, namely, a more universal character and penetration ability into tissues, easy dosage and control, higher locality and safety, molecular selectivity, and lower cost. A combination of methods developed and patented by us can form a technological platform for new-generation low-frequency magnetic theranostics which is significantly more effective and possesses more options than conventional radiofrequency theranostics.

By using electron microscopy and X-ray photoelectron spectroscopy (XPS), we show that the structure of support carbon materials—carbon nanofiber (CNF) and carbon nanotubes (CNTs)—affects the electronic state and dimensions of supported platinum particles that display a high catalytic activity in acetylene hydrogenation. Increasing the platinum load of Pt/CNF catalysts from 0.075 to 0.3 wt % results in the enhancement of their catalytic activity, while the selectivity for ethylene diminishes, which we attribute to the enlargement of the platinum nanoparticles. The XPS studies reveal that the platinum exists in, on average, a more oxidized state at the surface of CNTs when compared to CNF. The detection of substantial quantities of the residual chlorine at the surface of the prepared support materials allows us to relate the presence of the platinum in oxidized states to the existence of surface sites differing in quantity and the ability to stabilize platinum at the surface of nanocarbons. In addition, we have established that a fraction of the platinum in Pt/CNT catalysts is located inside of the CNTs. The differences between the states of CNT- and CNF-supported platinum nanoparticles affect catalyst selectivity: the Pt(0.075%)/CNT catalyst exhibits superior selectivity for ethylene hydrogenation than the Pt(0.075%)/CNF catalyst. The enhanced selectivity may be a consequence of the different electronic structures of the platinum in the considered catalysts and faster Knudsen diffusion of acetylene molecules, when compared to ethylene molecules, in CNT channels.

Ion-exchange membranes based on polymethylpentene and sulfonated polystyrene with different grafting degrees were obtained. Solvation and mobility of lithium ions depending on the composition of initial organic solvents were studied. The highest ionic conductivity at room temperature (30°C) are obtained for the membranes containing dimethylsulfoxide (σ = 1.31 × 10^–4 S/cm for membrane with GD = 78%). Membranes containing dimethylformamide are characterized by a constant phase composition in a broad temperature range and the highest ionic conductivity at low temperature (σ = 9 × 10^–6 S/cm at–20°C for a polymer with GD = 78%).

In this work, the high-temperature liquid-phase vacuum sintering of the nanocrystalline composition VC_0.40O_0.53–C_free with various nickel contents has been carried out. Based on the data of X-ray studies and raster electron microscopy with the assumption of energy-dispersion analysis, the diagram of the process has been suggested and its quantitative parameters have been determined depending on the composition of the initial mixtures.

The effect of selenium biocomposites obtained from medical macrobasidiomycetes Ganoderma lucidum, Grifola umbellata, Laetiporus sulphureus, Lentinula edodes, and Pleurotus ostreatus on the viability of the phytopathogenic gram-positive bacteria Clavibacter michiganensis subsp. sepedonicus (Cms) and its ability to form biofilms has been studied. A decrease in the viability of the bacterial cells as a result of incubation with biocomposites is shown. The determining effect of the selenium component of the composites on the studied biological activity is investigated. The dependence of the antimicrobial action of selenium-containing experimental samples on the biological species of the fungus is revealed. Biocomposites based on extracellular metabolites of Lentinula edodes and Ganoderma lucidum possess maximal activity. When biopolymer samples of fungal origin are added to the bacterial suspension, the ability of Cms to form biofilms differs depending on the type of biocomposite; it decreases significantly in some cases.

A unique method for the self-assembly of multilayer multichromic molecular crystals from three various polymethine dyes absorbing light in the broad spectral range has been developed. This method is based on the formation of an anionic platform of J-aggregates of magnesium complexes of thiamonomethinecyanines in an aqueous solution followed by the matrix synthesis of J-aggregates of two cationic trimethinecyanines on the surface of the platform. Spectral, luminescent, and photoelectric properties of the multichromic crystals of dyes have been studied. It has been shown that each multichromic organic crystal is a multilayer photoelement which possesses photoconductivity in three maxima of exciton absorption in the blue, green, and red spectral ranges with efficiency from 2.7 to 6.1%. The results form the basis for the technological development of high-organized molecular structures possessing unique optical and photoelectric properties with the aim of applying them in organic and hybrid organic/inorganic photonics and optoelectronics, including in the form of thin-film photoconverters in broad spectral ranges.

This paper reports the synthesis of nanocomposites of selenium and tellurium on a polymer matrix: arabinogalactan. Their physicochemical and biological properties are presented in detail. Studies of the parameters of acute toxicity and sex sensitivity to the nanocomposite of selenium and arabinogalactan show the following. The nanocomposite is characterized as a substance with a low acute toxicity hazard in the acute intragastric route of entry; no differences in the sex sensitivity of animals are revealed. The concentration dependences of the cytotoxicity of composites for human HEp-2 and ECV-304 cell cultures, as well as the green monkey kidney fibroblasts (Vero B), are studied during the investigation of biological properties of the nanocomposites of Te and Se with arabinogalactan. It is found that the Te and Se nanocomposites exhibit a different dependence of cytotoxicity on the concentration in all cultures studied. The nanocomposite of arabinogalactan with elemental selenium is shown to have a bactericidal effect against the causative agent of the ring rot of potato Clavibacter michiganensis subsp. sepedonicus.

Silver-containing nanocomposites are synthesized from humic peloid substances in an environmentally friendly way. The growth-stimulating activity of ultralow concentrations of humic substances of therapeutic muds and silver-containing compounds on their basis is studied. The stimulator active concentration range upon wheat seed generation is determined to be 4 × 10^–3–4 × 10^–16%. The fastest (almost double) growth of the main roots of sprouts is found to be for silver nanocomposites based on humic substances. The established activity of nanocomposites is a prerequisite for the development of novel highly efficient growth-stimulating drugs.

Based on the method of thermal solvent precipitation, unique procedures for drug capsulation have been developed. Biodegradable polymers, polycaprolactone, and polyethylene glycol are used. Hydrosols and alcosols of various metals and their compounds have been obtained, which makes the targeted delivery of the desired substance using a magnetic field possible. The importance of magnetite hydrosol in the stability of colloidal systems has been shown. Experiments on the impact of doxorubicin and capsulated doxorubicin on the HeLa cell culture are carried out. The studies are conducted in laboratory mice and the possibility of controlling magnetoactive particles in vivo is demonstrated.

The efficiency of zeolite modified with nanostructures (carbon nanotubes) has been studied upon removing anionic organic dye (methyl orange)—sodium 4-(4-dimethylaminophenylazo) benzenesulfonate)— from aqueous media. For quantitative characteristics of the sorption properties of the studied material, the experimental data are analyzed in the linearization coordinates of empirical Langmuir, Temkin, and Dubinin–Radushkevich equations at temperatures of 303, 313, and 323 K. The data correspond best to the following order of adsorption isotherms based on the correlation coefficient: Dubinin–Radushkevich > Temkin > Langmuir. It has been found that adsorption of sodium 4-(4-dimethylaminophenylazo) benzenesulfonate on zeolite, modified with nanostructures is a spontaneous endothermic process. The possibility of a significant increase in the adsorption capacity of zeolites by their volumetric modification by nanostructures is shown. According to the experimentally determined value of the sorption capacity, the studied modified zeolite is 2–5 times higher than the analogs.

This work shows the possibility of obtaining Al₂O₃–ZrO₂–Y₂O₃ medical ceramics from powders synthesized by nanospray drying. The powder is spheres with a uniform distribution of components: mixed oxides. It is shown that yttrium oxide, in addition to stabilizing the tetragonal phase of zirconium oxide in ceramics, causes a more deagglomerated structure of particles and, as a result, increases the degree of shrinkage of ceramics and the final temperature of active sintering from 1252 to 1468°C. The ceramics obtained by cold pressing with subsequent sintering have a hardness of 15.31 GPa and density of 92.8%; those obtained by the sintering method in spark discharge plasma have a hardness of 16.05 GPa and density of 99.21%.