Askar D. Turashev

Lead and mercury are among the most dangerous environmental pollutants due to their high toxicity to humans and other living organisms. They are also ubiquitous in our ecosystems as a result of industrial waste. Therefore, it is essential to develop a simple and inexpensive method to rapidly detect low concentrations of these metals in various liquids, including wastewater. Aptamer-based electrolyte-gated organic field-effect transistors (EGOFETs), which are traditionally used to detect large biomolecules such as viruses and proteins, are a promising concept for heavy-metal detection. To achieve this, we chose several aptamers with high affinity for and specificity to Pb²⁺ and Hg²⁺ ions, determined the dissociation constants and stoichiometry of the complexes, investigated the kinetics of complex formation and cross-specificity and proposed structures for the aptamer–cation complexes. Based on these aptamers, we developed EGOFET-based aptasensors for Pb²⁺ and Hg²⁺. The fabricated EGOFET devices have been shown to be sensitive to low concentrations of lead (from 30 nM to 2.5 μM) and mercury (from 250 nM to 2.5 μM) cations. These ranges correspond to the maximum permissible concentrations in drinking and wastewater for lead, which are 144 nM and 1.2 μM, respectively, and exceed the range of maximum permissible concentration in drinking and wastewater for mercury, which is 5 nM. Despite this, it was possible to detect mercury cations at a concentration of 5 nM within five minutes in a model system that simulates liquid flow using the EGOFET device. This demonstrates the potential for fast and selective detection of Pb²⁺ and Hg²⁺ ions at maximum permissible concentrations in drinking water using EGOFET-based aptasensors. This is a significant step forward in the development of flow sensors for detecting heavy metals in liquid media.

The Omicron strain is currently the main dominant variant of SARS-CoV-2, with a large number of sublineages. In this article, we present our experience in tracing it in Russia using molecular diagnostic methods. For this purpose, different approaches were used; for example, we developed multiprimer panels for RT-PCR and Sanger and NGS sequencing methods. For the centralized collection and analysis of samples, the VGARus database was developed, which currently includes more than 300,000 viral sequences.

The luminal surface of a blood vessel accommodates a complex multicomponent system of mainly carbohydrates and proteins called glycocalyx. According to the concept of the double protective layer, glycocalyx is the first protection barrier of the vascular wall. The structure of glycocalyx is determined by a group of proteoglycans, glycoproteins, and glycosaminoglycans. Two groups of molecules are distinguished within the glycocalyx constituents, that is, membrane proteoglycans (syndecans and glypicans bound to endothelial cell membranes) and soluble proteoglycans (perlecan, biglycan, versican, decorin, and mimecan). There are five types of glycosaminoglycan chains; these are heperan sulfate, chondroitin sulfate, dermatan sulfate, keratan sulfate, and hyaluronan. There is a dynamic equilibrium between the soluble components of glycocalyx and flowing blood, which allows for separation of the endothelial surface layer. Due to its complexity and location at the interface of blood circulation system, glycocalyx is involved in the maintenance of vascular homeostasis. Here, the molecular composition of glycocalyx, properties of its components, biosynthesis, and common structural features are discussed.

The progress in reperfusion therapy dictated the necessity for developing new tools and procedures for adjacent/additional therapy of acute cardiovascular disorders. The adjacent therapy is targeted on the damage of the microcirculation, leading to the unfavorable prognosis for the patients. The no-reflow phenomenon holds special place in the multifactorial etiology of the microcirculation disorders, offering a new challenge in treating the patients associated with ST-segment elevation on ECG at myocardial infarction. One of the numerous causes of no-reflow, the influence of the endothelial glycocalyx of the microcirculation, is analyzed. The results obtained in the studies of the endothelial glycocalyx ultrastructure are generalized, the effect that the fragments of the glycocalyx glycosaminoglycans have on the function of the vascular wall is demonstrated. The trends in searching for correlations between the thickness of the capillary glycocalyx and the cardiovascular disease risk are noted.