The swelling of a polymer ion-exchange membrane Nafion in water with various heavy isotope contents (D2O) was studied by photoluminescent UV spectroscopy. The photoluminescence arises because of the presence of sulfonic groups attached to the ends of the perfluorovinyl ether groups that form the tetrafluoroethylene (Teflon) backbone of Nafion. The width of the colloidal region, which is formed near the membrane surface as a result of the outgrowth of Nafion microfibers toward the bulk liquid, varies non-monotonically with D2O content, displaying a narrow maximum in the low concentration region. A significant insight into the unexpected isotopic effects revealed in swelling Nafion in deuterated water is provided. Mainly, the polymer swelling is very sensitive to small changes (on the order of several tens of parts per million) in the content of deuterium, which, for instance, can help in understanding the isotopic effects in living tissues.

Data on physicochemical properties of the light water (deuterium concentration is reduced to the ratio D/H = 4 ppm and that of the isotope of oxygen 18—to the ratio 18O/16O = 750 ppm) have been obtained. They include the melting and boiling points, kinematic viscosity, density, the spin-spin proton relaxation time, self-diffusion coefficients, and the small-angle laser light scattering. It was found out that the biological activity of the light water was determined by the mechanisms different from the ligand-induced toxic effects. An explanation was proposed for the detected significant changes of the light water as compared with the high-resistivity water having geochemically ordinary isotope composition. This explanation was based on the mechanism of formation of supramolecular density inhomogeneities in water representing the deuterium-stabilized heterophase clusters.

Peculiarities of the vital activity of organisms at different concentrations of the D/H isotope ratio in water have been studied. It was established that many organisms react in different ways to...

It has recently been shown that the titer of the SARS-CoV-2 virus decreases in a cell culture when the cell suspension is irradiated with electromagnetic waves at a frequency of 95 GHz. We assumed that a frequency range in the gigahertz and sub-terahertz ranges was one of the key aspects in the “tuning” of flickering dipoles in the dispersion interaction process of the surfaces of supramolecular structures. To verify this assumption, the intrinsic thermal radio emission in the gigahertz range of the following nanoparticles was studied: virus-like particles (VLP) of SARS-CoV-2 and rotavirus A, monoclonal antibodies to various RBD epitopes of SARS-CoV-2, interferon-α, antibodies to interferon-γ, humic–fulvic acids, and silver proteinate. At 37 °C or when activated by light with λ = 412 nm, these particles all demonstrated an increased (by two orders of magnitude compared to the background) level of electromagnetic radiation in the microwave range. The thermal radio emission flux density specifically depended on the type of nanoparticles, their concentration, and the method of their activation. The thermal radio emission flux density was capable of reaching 20 μW/(m² sr). The thermal radio emission significantly exceeded the background only for nanoparticles with a complex surface shape (nonconvex polyhedra), while the thermal radio emission from spherical nanoparticles (latex spheres, serum albumin, and micelles) did not differ from the background. The spectral range of the emission apparently exceeded the frequencies of the Ka band (above 30 GHz). It was assumed that the complex shape of the nanoparticles contributed to the formation of temporary dipoles which, at a distance of up to 100 nm and due to the formation of an ultrahigh strength field, led to the formation of plasma-like surface regions that acted as emitters in the millimeter range. Such a mechanism makes it possible to explain many phenomena of the biological activity of nanoparticles, including the antibacterial properties of surfaces.

A kinetic method of biotesting of aqueous solutions using isolated cells of unicellular organism Spirostomum ambigua has been described. A kinetic scheme of interaction of cellular biosensor with ligands based on the Michaelis-Menten mechanism was proposed. It was shown that the death rate of S. ambigua featured the Arrhenius-type dependence on temperature. The activation energy was determined for different toxicants and drugs. For many compounds the activation energy of slow stage of the process of cellular biosensor death linearly correlates with parameter DL₅₀ for the same substances at their oral administration to laboratory animals.