Nanotechnologies in Russia最新文献

Hybrid electrically conductive materials were obtained by the synthesis of a polyaniline-based conductive layer on fibrous matrices. Nonconductive nonwoven fabrics with fibers 0.5–13.5 μm in diameter were produced by electrospinning from solutions and melts of a number of commodity polymers. The influence of the surface properties of the initial matrices on the polyaniline synthesis process and electrophysical characteristics of the hybrid conductive materials was studied. It was shown that for highly hydrophobic matrices synthesis of the conductive layer occurs only on the upper layers of fibers, which causes much lower conductivity (10^–4 S/cm and less) compared to wettable matrices, where synthesis occurs over the entire volume of the nonwoven fabric, and conductivity reaches 5 × 10^–2 S/cm.

A promising strategy for combating pathologies associated with oxidative stress is the use of mitochondria-targeted drugs. One of them is the positively charged tetrapeptide SS-20, which is able to penetrate into mitochondria. The effect of SS-20 on isolated supercoupled rat-liver mitochondria is studied. It is shown that SS-20 decreases hydrogen peroxide production, inhibits the opening of the nonspecific Ca²⁺/Pi-dependent mitochondrial pore, does not exhibit uncoupling activity, does not inhibit mitochondrial respiration, and does not reduce their membrane potential. In the aerobic yeast Dipodascus magnusii, SS-20 reduced the level of oxidative stress in yeast and prevented prooxidant-induced mitochondrial fragmentation.

Recording the activity of brain neurons opens up many possibilities for both diagnosing diseases and expanding human capabilities. Classic metal electrodes are inevitably rejected by nervous tissue due to their physical properties, and hence have a number of significant limitations in use. Hydrogels may be more suitable materials for this role, since they make it relatively easy to achieve the required properties by simply combining different polymers. This work presents an electrically conductive hydrogel based on poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS), carrageenan (CRG), and polyvinyl alcohol (PVA), which has already proven itself as a stable and biocompatible material. This series of experiments on C57Bl/6 mice demonstrates its feasibility as an electrocorticography electrode.

The results of determination of the static permittivity of individual red blood cells (RBCs) and their membranes by dc-electrostatic force microscopy are presented. This method is based on a quantitative analysis of the cross-sectional profiles of experimental electrostatic images. A model of electrostatic interaction between the cantilever tip and a biological cell of disk shape is proposed. The obtained permittivity of individual RBCs agrees well with published data. Calculation of the permittivity by the effective medium approximation for RBCs is performed for comparison with the mean value of the RBC permittivity of our model.

Selenium-containing nanoscale systems stabilized with alkyldimethylamine oxide are obtained. Based on computer quantum-chemical modeling, it is established that alkyldimethylamine oxide is the optimal stabilizer. During optimization of the synthesis technique, the optimal concentrations of the components are established: C (selenous acid) = 0.3536 mol/L, C (alkyldimethylamine oxide) = 0.0339 mol/L, C (ascorbic acid) = 0.0992 mol/L. This sample is examined using the transmission-electron-microscopy method. The stability of the sample is established in the concentration range of NaCl, BaCl₂, and FeCl₃ salts up to 0.5 mol/L, and Na₂SO₄ and K₃PO₄ salts up to 0.1 mol/L, as well as in the pH range from 8 to 12.

The biomass of phototrophic microorganisms (cyanobacteria and microalgae) is widely used in the food, feed, and pharmaceutical industries. Extracts from the biomass of microalgae and cyanobacteria, as well as various groups of compounds (lipids, peptides, polysaccharides, pigments, etc.) have a wide range of biological activity, which makes microalgae and cyanobacteria a very promising source of a wide variety of new bioactive molecules for inclusion in cosmetic formulations to combat the signs of aging, in sunscreens, bleaching agents, wound-healing preparations, etc. This review focuses on the use of phototrophic microorganisms in cosmetic products based on their biological activity.

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.

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.

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.

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.