Nanotechnologies in Russia最新文献

The beneficial properties of probiotic bacteria are well known. It has recently been established that these properties are largely due to extracellular vesicles (EVs). EVs produced by bacterial cells transport a wide range of compounds (proteins, lipids, polysaccharides, metabolites, DNA, RNA, including small RNA). The specifics of the physical and chemical properties and composition of EVs determine the characteristics of their biological activity. EVs are enriched with bioactive molecules that can mediate the modulation of signaling pathways and reprogramming of target cells. The size (20–300 nm), biocompatibility, and ability to deliver drugs to different organs and tissues make EVs of probiotics a promising tool for practical application in medicine. Experimental data obtained in recent years have revealed the great potential of probiotic EVs for immunocorrection, the treatment of a number of skin diseases, digestive disorders, metabolic, and psychoneurological disorders, as well as oncological diseases. This has determined the rapid growth of interest in probiotic EVs as postbiotics, fundamentally new drugs and their delivery vehicles, new types of vaccines, and tools for cancer therapy. The realization of emerging prospects requires the comprehensive structural and functional characterization of probiotic EVs. This review presents an analysis of publications devoted to the characterization of probiotic EVs from the point of view of problems and prospects for fundamental research and the practical application of these nanostructures, the development of new scientific directions, and the development of a biosafety system.

For therapeutic applications it is important to know quantitative uptake of nanoparticles by the cells. In this work incorporation of superparamagnetic iron oxide nanoparticles (SPIONs) coated by the dextran shell into malignant glioma cells, as well as into human fibroblast cells in vitro was studied. Nanoparticles were synthesized by co-precipitation and the presence of chemical impurities in them was assessed by X-ray fluorescence measurements. Geometrical parameters of nanoparticles were characterized by X-ray diffraction and dynamic light scattering. Magnetic and dynamic parameters of SPIONs in the medium before co-incubation with cells as well as in cells after incubation were found using highly sensitive method of nonlinear response to a weak ac magnetic field parallel to the steady field with registration of the second harmonic of magnetization M₂ followed by processing the obtained data with the formalism based on the Gilbert-Landau-Lifshitz equation for stochastic dynamics of superparamagnetic particles. The formation of SPION aggregates in the incubation medium was established, accompanied by a decrease in magnetostatic and, accordingly, free energy of the SPIONs system. The uptake of SPIONs by the cells at co-incubation was studied depending on the concentration of nanoparticles, duration of the co-incubation and the seeding density. The data obtained indicate: (i) close values of the magnetic and dynamic parameters of nanoparticle aggregates absorbed by the cells and in the medium before incubation; (ii) the decrease in the amount of SPIONs absorbed by cells at a higher seeding density; (iii) dependence of the SPIONs uptake on their concentration (characterized by the iron content) in the medium and on the time of co-incubation as well as on the cell type, with minimal uptake by cells of normal morphology.

Multi-walled carbon nanotubes (MWCNTs) are functionalized with –OH, –SH, –NH₂, and (3‑glycidyloxypropyl)trimethoxysilane (GLYMO) groups. The enzymatic activity of nanobiocatalysts prepared on the basis of amidase and nitrile hydratase isolated from the cells of the proteobacterium Alcaligenes faecalis 2 and the actinobacterium Rhodococcus ruber gt 1, respectively, and adsorbed on the functionalized MWCNTs (fMWCNTs), is determined. Also, nanobiocatalysts are prepared by aggregating bacterial cells with fMWCNTs; the value of cell aggregation and the manifestation of their enzymatic activity are determined. It is determined that R. ruber gt 1 cells aggregate with all carbon nanomaterials within the range of 16–70 mg/g, and for A. faecalis 2 cells, within the range of 4–84 mg/g. The smallest number of cells are bound to MWCNT–GLYMO, while the high enzymatic activity of the aggregates is retained. Aggregates of A. faecalis 2 with MWCNT–SH exhibit amidase activity exceeding that of native cells. Amidase and nitrile hydratase are bound to nanomaterials to a much lesser extent (no more than 1.7 mg/g). The effect of fMWCNTs on bacterial biofilm formation is studied and a decrease in the total biomass of A. faecalis 2 biofilms, as well as the metabolic activity of their cells, is shown, especially in the presence of MWCNTs-SH and MWCNTs-GLYMO. At the same time, biofilm formation by R. ruber gt 1 in the presence of fMWCNTs increases. Nanobiocatalysts have prospects for practical use due to the advantages of the immobilization of enzymes and microbial cells, as well as a high dispersity and high active surface area of the material.

The goal of the work is to create a new generation of highly effective antitumor drugs for photodynamic therapy (PDT), a method based on the interaction of light with a photosensitizer (PS), localized primarily in cancer-affected tissue, which leads to the formation of cytotoxic forms of oxygen and the death of cancer cells. Hybrid three-component nanosystems (HTNs) are synthesized based on selenium (Se⁰) nanoparticles (NPs), the photosensitizer Radachlorin (RC) and polymer carriers (PСs), i.e., graft copolymers with a polyimide or cellulose main chain and side chains of polymethacrylic acid (PMAA). Using ultraviolet (UV) spectroscopy, the formation of a HTNs is proven, presumably due to the hydrophobic interactions of selenium NPs with the methyl groups of the PСs (1st stage), followed by the incorporation of Se⁰ NPs of the metal-porphyrin complex type inside the porphyrin ring of RС (2nd stage). For all studied HTNs, discrete spherical nanostructures with a diameter of D_AFM = 80–400 nm are revealed by AFM. The synthesized HTNs are promising as photosensitive compounds for the treatment and diagnosis of oncological diseases by the PDT method.

Block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine and poly-2-methyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine. Using NMR spectroscopy, it was determined that in copolymers the component fraction varies in a tenfold range. The hydrodynamic characteristics of the synthesized copolymers were determined using molecular hydrodynamics and optics methods and it was shown that they are flexible-chain polymers with an equilibrium rigidity of about 2 nm. The behavior of block copolymers in water-salt solutions depends on the content of blocks: an increase in the fraction of the more hydrophobic poly-2-isopropyl-5,6-dihydrooxazine leads to a decrease in the phase separation temperature and LCST. The addition of NaCl leads to a slight decrease in the phase separation temperature.

Based on a combination of modeling and structural analysis methods with immunoinformatic algorithms for digital prediction, structural elements, i.e., subdomains, also called antigenic domains, enriched in B- and T-cell antigenic determinants (epitopes), of the surface ectodomain of glycoprotein B (EctoGB) of human herpes simplex virus type 2 are found and their immunogenicity, allergenicity, and toxicity are predicted. It is established that the proximal β-ribbon domain of EctoGB (subP) adjacent to the viral envelope has the maximum immunogenic potential, which corresponds to the results of an experimental analysis carried out on the EctoGB model of human herpes virus type 5. Further studies of subP will contribute to the development of a new antiherpetic vaccine, and the proposed methodology can be used to search for antigenic domains of viruses of various families.

The work presents the results of testing nonwoven fibrous matrices based on poly-L-lactide modified with biopolymers (chitosan and collagen) under in situ stretching in a scanning electron microscope (SEM) chamber operating in the environmental mode. Matrix stress-strain curves and SEM images are obtained simultaneously during uniaxial stretching of the matrices until rupture. The change in the mechanical characteristics of the matrices during degradation is studied depending on the time of their incubation in the culture medium.

The object of study was human sweat-based sensors printed on paper and spunlace nonwoven fabric using ink consisting of graphene and the conductive polymer PEDOT:PSS. In glucose identification, the 2D layers have demonstrated resistance decrease by three to five orders of magnitude. The influence of the printed layer structure on the sensor sensitivity has been established. A maximum sensitivity was observed for two to three printed layers, when most graphene flakes in the layers were located vertically and thus ensured presence of active states in the layer, at the flake boundaries. At elevated humidity, a spectrum of electrically active states appeared with a maximum at an energy of ~0.36–0.40 eV, and these electrically active states provided conductivity. It is assumed that adsorption of glucose molecules occurred on the edge states of graphene flakes, and they also acted as a catalyst for glucose oxidation. As a result, the conductivity increased sharply, depending on the additional carriers resulting from the glucose oxidation. The sharp decrease in the sensitivity and selectivity in thicker films of the same composite is associated with the change in the structure of the layers: there arise clusters of the material without free edge states of graphene flakes. The non-invasive sensors created combine ease of manufacture and low cost with high sensitivity.

This work presents the results of comparative studies of the effect of iron, zinc, copper nanoparticles (NPs) and their compositions, and chitosan in nutrient media on seed germination and the morphophysiological parameters of tomatoes and peppers. It is found that for nutrient media containing chitosan and metal NPs instead of salts of these elements, the germination of pepper seeds increased on average by 3–7% and tomato seeds by 1.4–2.8 times compared to the germination of seeds on standard Murashige—Skoog medium (control), depending on the concentration, element, and combination with chitosan. The introduction of metal NPs and chitosan into the nutrient media for the cultivation of tomato and pepper plants has an insignificant effect on a change in root length, but promotes an increase in its activity, for example, for Fe NPs at a concentration of 3 mg/L by 2.24 times (p ≤ 0.05), in combination with chitosan by 2.44 times (p ≤ 0.05) compared to the control. Plant material prepared on nutrient media with metal NPs and chitosan in aseptic conditions, planted into the soil, allows an increase in the yield of tomatoes by 10–15% and peppers by 2 times.

The data on changes in bacterial luminescence and morphometric indicators of spring durum wheat (Triticum durum Desf.), spring barley (Hordeum sativum J.) and proso millet (Panicum miliaceum L.) after pre-sowing seed treatment with boron and cobalt nanoparticles in a polymer matrix are presented. The toxicity results of B and Co NPs on the bacterial luminescence test system for Escherichia coli K12 TG1 show that the semi-lethal (causing 50% of bacteria death) concentration of B NPs is 2.4 × 10^–2 mg/mL and Co NPs is 3 × 10^–3 mg/mL, whereas the selected concentration range for pre-sowing seed treatment is from 10^–9 to 10^–7%. The germination energy increases by 10.9‒25%, and seed germination by 2.9‒10.7%. Studying the morphometric parameters of shoots after NP treatment showed that cobalt has a more intensive effect on the growth of the superterrestrial parts of plants, and boron has better stimulation of the growth of the root system. In the case of B NPs, the sprout length increases by 4.8‒31.3% the root-system length increases by 14.9‒32%, the dry mass of the sprout by 14.3‒26.1%, and the dry mass of the root system by 17.9‒29% in comparison with the control. The pre-sowing seed treatment of cereal crops with Co NPs also shows an increase in shoot length by 29‒49%, root-system length by 12‒17%, sprout mass by 18‒36%, and root mass by 10‒20% relative to the control samples. A concentration of boron NPs of 10^–8% and cobalt NPs of 10^‒9% can be recommended for further production tests in the field.