I. S. Ryzhkina

Formation of nanoassociates as a key to understanding of physicochemical and biological properties of highly dilute aqueous solutions

On the grounds of experimental data obtained by a set of physicochemical methods (dynamic light scattering, microelectrophoresis, conductometry, tensiometry, pH-metry, dielcometry, polarimetry, atomic force microscopy, and UV and ESR spectroscopy), a previously unknown fundamental phenomenon was discovered, namely, the formation nanosized molecular assemblies, so-called nanoassociates, in aqueous solutions of low concentrations prepared by successive serial dilutions. The formation and concentration rearrangements of nanoassociates may be responsible for physicochemical and biological properties of highly dilute aqueous solutions. The formation of nanoassociates is initiated by a solute under certain conditions, most essential among them being the presence of external physical fields (geomagnetic and low-frequency electromagnetic fields) and particular structure of the substance.

Self-assembly of an aminoalkylated resorcinarene in aqueous media: host–guest properties

A new water-soluble resorcinarene, with a negatively-charged lower rim and a positively-charged upper rim self-assembles into supramolecular oligomers to bind 1,5-diaminonaphthalene in water.

Nanoassociate formation in highly diluted water solutions of potassium phenosan with and without permalloy shielding

Abstracts Diluted water solutions of anti-oxidant potassium phenosan, kept before explorations in “usual” conditions and in conditions of “permalloy container”, i.e. shielding of solution from the influence of external low-frequency electromagnetic and/or geomagnetic fields, were studied. It is shown that in solutions kept in shielded conditions in the area of high dilution with a concentration of solutions lower than “threshold”, nanoobjects called “nanoassociates”, are not formed, and anomalous physicochemical and biological properties observed in solutions kept in “usual” conditions, are not found. We conclude that anomalous physicochemical and biological properties of highly diluted water solutions of potassium phenosan made under “usual” conditions are determined by “nanoassociates”, in which an external low-frequency electromagnetic and/or geomagnetic field is a necessary condition of the formation.

Comparative study of self-organization and physicochemical properties of highly diluted aqueous solutions of phenol bioantioxidants

203 Applying a methodological approach suggested by us to different compounds (organic and inorganic salts, amphiphilic and lipophilic compounds), physic ochemical substantiation of the effect of ultralow con centrations and electromagnetic fields has been devel oped for the first time. This substantiation makes it possible to work out a convincing concept of the exist ence of nonlinear changes in physicochemical proper ties (electrical conductivity, surface tension, pH, cata lytic activity) and of the appearance of bioeffects of solutions of biologically active compounds (BACs) in the range of low and ultralow concentrations [1–6]. The effect consists in solute initiated formation of nanosized (D up to 400 nm, ζ potential ranges from –2 to –20 mV) structures (nanoassociates) composed mainly of water molecules in aqueous solutions of dif ferent compounds of ultralow concentration. The change in the nanoassociate parameters (D, ζ poten tial) with a change in the solute concentration corre lates with the concentration induced change in the physicochemical and biological properties of solu tions. Compounds capable and incapable of exhibiting this effect have been discovered. However, it is still unclear how the structure of a compound affects the formation of nanoassociates and physicochemical properties of solutions of low concentration. With the aim of elucidating the effect of the struc ture of a compound on the formation of nanoassoci ates, in this work, we studied the self organization and physicochemical properties of solutions of some 2,6 dialkylphenol derivatives—synthetic potassium phe nosan (1) and Ichphan C 10 (2) and natural α toco pherol (3)—capable of forming nanoassociates [1, 2, 5, 6] and manifesting biological activity in highly diluted aqueous solutions [7–11]. The selected com pounds have a sterically hindered hydroxyl group responsible for the antioxidant properties of com pounds 1–3 and different substituents in the benzene ring responsible for hydrophilicity (1), amphiphilicity (2), and hydrophobicity (3) of these BACs.

Dielectric spectroscopy study of low-concentration aqueous solutions of a calix[4]resorcinarene derivative

ISSN 00125016, Doklady Physical Chemis try, 2014, Vol. 455, Part 2, pp. 56–59.

Aggregation behavior and catalytic activity of systems based on calix[4]resorcinarene derivatives and surfactants. 1. Mixed micellization of aminomethylated calix[4]resorcinarenes with cetyltrimethylammonium bromide in aqueous dimethylformamide

Mixed micellization of amphiphilic aminomethylated calix[4]resorcinarenes and phenols, which are their structural units, with the cationic surfactant cetyltrimethylammonium bromide (CTAB) in aqueous 10—70 vol % DMF decreases the critical micelle concentration; the resulting aggregates are larger than those in the CTAB—DMF—water systems. The micellization of CTAB with aminomethylated calix[4]resorcinarenes proceeds in two steps, while its micellization with phenols is a single-step process. The micellization characteristics depend on the structure and hydrophobicity of the amphiphilic compound and the concentration of DMF.

Self-organization and properties of dilute aqueous solutions of cetyltrimethylammonium bromide in a range of physiologically important temperatures

A combination of physicochemical methods (dynamic light scattering, nanoparticle tracking analysis, conductometry, tensiometry, and ESR spectroscopy) revealed that dilute solutions (1•10–3, 1.0•10–4, 1.0•10–7, and 1.0•10–9 mol L–1) of surfactant (cetyltrimethylammonium bromide) in a temperature range of 25—45 °C are self-organized dispersed systems. As the temperature increases, the systems undergo rearrangements specific for each studied concentration, which is reflected as nonmonotonic temperature dependences of the parameters of domains (1•10–3 and 1.0•10–4 mol L–1) and nanoassociates (1.0•10–7 and 1.0•10–9 mol L–1) and also as interrelated dependences of the conductivity of solutions with extremes at 30, 37, and 40 °C. The ESR experiments show a nonmonotonic decrease in the rotational diffusion correlation time (τcor) of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in the temperature dependences of τcor with the temperature increase from 25 to 45 °C and the appearance of two to three plateaus, one of which (in a range of 36—40 °C) is observed in the temperature dependences for all studied concentrations.

Influence of spatial isomerism of tetrathiacalix[4]arene functionalized by hydrazide groups on self-organization and physicochemical properties of aqueous dimethyl sulfoxide solutions of low concentration

264 Recently, we have discovered a new phenomenon that opens the way to elucidating the mechanism of the effect of weak action of different nature on living organisms [1–5]. This phenomenon, referred to as “effect of ultralow concentrations and electromag netic fields” [2], consists in the formation of nano sized molecular ensembles, so called nanoassociates, in aqueous solutions of low concentrations. The nanoassociate formation is responsible for the emer gence of unique physicochemical properties of dilute solutions and, which is especially important, corre lates with bioeffects of these solutions [3, 4]. Forma tion of nanoassociates is initiated by a solute under certain conditions, the most essential among which are the presence of external electromagnetic fields and a definite structure of a substance [5].

Single-electron oxidation and nucleophilicity of aminomethylated calix[4]resorcinarenes

The electrochemical oxidation of a number of aminomethylated calix[4]resorcinarenes (AMC) with different substituents at the nitrogen atom and the kinetics of nucleophilic substitution reactions of these compounds with p-nitrophenyl bis(chloromethyl)phosphinate were studied. The reactivity of the ionic associates of AMC in the nucleophilic substitution and the behavior of AMC in electrooxidation are determined by the same factors, namely, the amino-group basicity and the nature of the substituents at the nitrogen atom. These factors influence the ratio of the zwitter-ionic and anionic forms of AMC.

Sterol binding by methyl‐β‐cyclodextrin and nystatin – comparative analysis of biochemical and physiological consequences for plants

The dependence of membrane function on its sterol component has been intensively studied with model lipids and isolated animal membranes, but to a much lesser extent with plant membranes. Depleting membrane sterols could be predicted to have a strong effect on membrane activity and have harmful physiological consequences. In this study, we characterized membrane lipid composition, membrane permeability for ions, some physiological parameters, such as H2O2 accumulation, formation of autophagosomal vacuoles, and expression of peroxidase and autophagic genes, and cell viability in the roots of wheat (Triticum aestivum L.) seedlings in the presence of two agents that specifically bind to endogenous sterols. The polyene antibiotic nystatin binds to endogenous sterols, forming so‐called ‘nystatin pores’ or ‘channels’ in the membrane, and methyl‐β‐cyclodextrin has the capacity to sequester sterols in its hydrophobic core. Unexpectedly, although application of both methyl‐β‐cyclodextrin and nystatin reduced the sterol content, their effects on membrane permeability, oxidative status and autophagosome formation in roots differed dramatically. For comparison, we also tested the effects of the antibiotic gramicidin S, which does not bind to sterols but forms nonspecific channels in the membrane. Gramicidin S considerably increased membrane permeability, caused oxidative stress, and reduced cell viability. Our results suggest that a decrease in the sterol content is, in itself, not sufficient to have deleterious effects on a cell. The disturbance of membrane integrity, rather than the decrease in the sterol content, is responsible for the toxicity of sterol‐binding compounds.