Search Results (6)

The aim of this research was to study the effect of Mn_xO_y nanoparticles stabilized with L-methionine on the morphofunctional characteristics of the barley (Hordeum vulgare L.) crop. Mn_xO_y nanoparticles stabilized with L-methionine were synthesized using potassium permanganate and L-methionine. We established that Mn_xO_y nanoparticles have a diameter of 15 to 30 nm. According to quantum chemical modeling and IR spectroscopy, it is shown that the interaction of Mn_xO_y nanoparticles with L-methionine occurs through the amino group. It is found that Mn_xO_y nanoparticles stabilized with L-methionine have positive effects on the roots and seedling length, as well as the seed germination energy. The effect of Mn_xO_y nanoparticles on Hordeum vulgare L. seeds is nonlinear. At a concentration of 0.05 mg/mL, there was a statistically significant increase in the length of seedlings by 68% compared to the control group. We found that the root lengths of samples treated with Mn_xO_y nanoparticle sols with a concentration of 0.05 mg/mL were 62.8%, 32.7%, and 158.9% higher compared to samples treated with L-methionine, KMnO₄, and the control sample, respectively. We have shown that at a concentration of 0.05 mg/mL, the germination energy of seeds increases by 50.0% compared to the control sample, by 10.0% compared to the samples treated with L-methionine, and by 13.8% compared to the samples treated with KMnO₄. Full article

In this work, CeO₂ nanoparticles, as well as CeO₂ nanocomposites with plasmonic silver nanoparticles, were synthesized using a simple sol-gel process. The concentration of silver in the composites varied from 0.031–0.25 wt%. Cerium hydroxide dried gel was calcined at temperatures from 125 to 800 °C to obtain CeO₂. It was shown that, at an annealing temperature of 650 °C, single-phase CeO₂ nanopowders with an average particle size in the range of 10–20 nm can be obtained. The study of acid-base properties showed that with an increase in the calcination temperature from 500 to 650 °C, the concentration of active centers with pKa 9.4 and 6.4 sharply increases. An analysis of the acid-base properties of CeO₂-Ag nanocomposites showed that with an increase in the silver concentration, the concentration of centers with pKa 4.1 decreases, and the number of active centers with pKa 7.4 increases. In a model experiment on dye photodegradation, it was shown that the resulting CeO₂ and CeO₂-Ag nanopowders have photocatalytic activity. CeO₂-Ag nanocomposites, regardless of the silver concentration, demonstrated better photocatalytic activity than pure nanosized CeO₂. Full article

This article presents the results of the synthesis of Se NPs stabilized by a quaternary ammonium compound—catamine AB. Se NPs were obtained by chemical reduction in an aqueous medium. In the first stage of this study, the method of synthesis of Se NPs was optimized by a multifactorial experiment. The radius of the obtained samples was studied by dynamic light scattering, and the electrokinetic potential was studied using acoustic and electroacoustic spectrometry. Subsequently, the samples were studied by transmission electron microscopy, and the analysis of the data showed that a bimodal distribution is observed in negatively charged particles, where one fraction is represented by spheres with a diameter of 45 nm, and the second by 1 to 10 nm. In turn, positive Se NPs have a diameter of about 70 nm. In the next stage, the influence of the active acidity of the medium on the stability of Se NPs was studied. An analysis of the obtained data showed that both sols of Se NPs exhibit aggregative stability in the pH range from 2 to 6, while an increase in pH to an alkaline medium is accompanied by a loss of particle stability. Next, we studied the effect of ionic strength on the aggregative stability of Se NPs sols. It was found that negatively charged ions have a significant effect on the particle size of the positive sol of Se NPs, while the particle size of the negative sol is affected by positively charged ions. Full article

This work presents the development of a method for the synthesis of calcium silicate nanoparticles stabilized with essential amino acids. CaSiO₃ nanoparticles were obtained through chemical precipitation. In the first stage, the optimal calcium-containing precursor was determined. The samples were examined using scanning electron microscopy. It was found that Ca(CH₃COO)₂ was the optimal calcium-containing precursor. Then, the phase composition of calcium silicate was studied using X-ray phase analysis. The results showed the presence of high-intensity bands in the diffractogram, which characterized the phase of the nanosized CaSiO₃—wollastonite. In the next stage, the influence of the type of amino acid on the microstructure of calcium silicate was studied. The amnio acids studied were valine, L-leucine, L-isoleucine, L-methionine, L-threonine, L-lysine, L-phenylalanine, and L-tryptophan. The analysis of the SEM micrographs showed that the addition of amino acids did not significantly affect the morphology of the CaSiO₃ samples. The surface of the CaSiO₃ samples, both without a stabilizer and with amino acids, was represented by irregularly shaped aggregates consisting of nanoparticles with a diameter of 50–400 nm. Further, in order to determine the optimal amino acid to use to stabilize nanoparticles, computerized quantum chemical modeling was carried out. Analysis of the data obtained showed that the most energetically favorable interaction was the CaSiO₃–L-methionine configuration, where the interaction occurs through the amino group of the amino acid; the energy value of which was −2058.497 kcal/mol. To confirm the simulation results, the samples were examined using IR spectroscopy. An analysis of the results showed that the interaction of calcium silicate with L-methionine occurs via the formation of a bond through the NH₃⁺ group of the amino acid. Full article

A method for the synthesis of ZnO nanoparticles (ZnO NPs) gels was developed. ZnO NPs were obtained through a sol–gel method with zinc acetate usage as a precursor. Optimization of the method of synthesis of ZnO NPs gel has been carried out. It was observed that the most stable ZnO NPs gels are formed at room temperature, pH = 8 and molar concentration of zinc C(Zn²⁺) = 0.05–0.2 M. It was shown that the addition of polysaccharide significantly affects the rheological properties and microstructure of ZnO NPs gels. We found that the optimal polysaccharide for the synthesis of ZnO NPs gels is hydroxyethyl cellulose. It is shown that the microstructure of a gel of ZnO NPs stabilized with hydroxyethyl cellulose is represented by irregularly shaped particles that are assembled into aggregates, with sizes ranging from 150 to 1400 nm. A significant hysteresis region is observed in a gel of ZnO NPs stabilized with hydroxyethyl cellulose. The process of interaction of ZnO NPs with polysaccharides was investigated. It was shown that the interaction of ZnO NPs with polysaccharides occurs through a charged hydroxyl group. In the experiment, a sample of a gel of ZnO NPs modified with hydroxyethyl cellulose was tested. It was shown that the gel of ZnO NPs modified with hydroxyethyl cellulose has a pronounced regenerative effect on burn wounds, which is significantly higher than that of the control group and the group treated with a gel of ZnO microparticles (MPs) and hydroxyethyl cellulose. It is also shown that the rate of healing of burn wounds in animals treated with gel of ZnO nanoparticles with hydroxyethyl cellulose (group 3) is 16.23% higher than in animals treated with gel of ZnO microparticles with hydroxyethyl cellulose (group 2), and 24.33% higher than in the control group treated with hydroxyethyl cellulose. The average rate of healing of burn wounds for the entire experimental period in experimental animals of group 3 is 1.26 and 1.54 times higher than in animals of group 2 and control group, respectively. An experimental study of a gel of ZnO NPs modified with hydroxyethyl cellulose has shown the effectiveness of its use in modeling the healing of skin wounds through primary tension. Full article

Within the framework of this study, the effect of nanoparticles of the essential trace element selenium stabilized by Polyvinylpirrolidone (PVP) C15 (8 ± 2 kDa) and ascorbic acid on the germination of barley seeds has been studied. Selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid, characterized by a spherical shape, monodisperse size distribution, and a diameter of about 70 ± 5 nm, were obtained by the chemical reduction method. The experiment compared the effect of selenium nanoparticles and selenous acid on seed germination. The positive effect of preparation of selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid on the length of roots and shoots, the number of roots, and the percentage of seed germination has been revealed. It was determined that the highest percentage of Hordeum vulgare L. culture seed germination was achieved using a preparation of selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid at a concentration of of 4.65 µg/mL. Analysis of the results showed that selenium in the form of nanoparticles has an order of magnitude that is less toxic than in the form of selenous acid. The study of morphological and functional parameters during the germination of Hordeum vulgare L. seeds allowed us to conclude that selenium nanoparticles can be successfully used in agronomy and agriculture to provide plants with the essential microelement selenium, which is necessary for the normal growth and development of crops. Full article