Diluted Aqueous Dispersed Systems of 4-Aminopyridine: The Relationship of Self-Organization, Physicochemical Properties, and Influence on the Electrical Characteristics of Neurons

A novel technique for studying the effects of technologically processed antibodies by evaluating the rate of oxidation of ascorbic acid during the reduction of the green-blue ABTS + radical

Since the pharmaceutical market is developing, there is a need for novel techniques for determining the physical-chemical properties of drug solutions. Drugs based on technologically processed antibodies (TPA) are an example of compounds that require a methodology for studying their effects. It has been shown that the process of external impacts during the manufacture of TPA-based drugs can induce breaking of intermolecular and intramolecular bonds in the solvent molecules, providing the emergence of new bonds with the molecules of the substance used for the manufacture of an active pharmaceutical ingredient. This article focuses on the technique applied for assessing the mentioned effect of TPA and consists in spectrophotometric observation of the oxidation process of ascorbic acid (AA) in the solution. The amount of oxidized AA was detected using ABTS·+(2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical-cation, which, when interacting with AA, is reduced and changes the color from green-blue to colorless. This technique showed the reproducibility of statistically significant differences in the amount of oxidized AA in the presence of TPA compared to controls and can be used to detect the changes in the properties of solutions exposed to the effect of the TPA samples.

Water as a sensor of weak impacts on biological systems

A characteristic feature of weak impacts is the non-monotonic response of living organisms and model biological systems to monotonically decreasing impacts. The qualitative similarity of the effects caused by the different acting factors makes one think about the common cause of the observed effects, which is water. A comprehensive analysis of the actual composition of water indicates that water under normal conditions is a multicomponent open non-equilibrium system. Nanobubbles that are always present in water play a significant role in the properties of dilute aqueous solutions. When collapsed, they can produce active oxygen and nitrogen species that have a strong effect on biological systems. Significant non-monotonic changes in electrical conductivity found in a series of sequentially diluted solutions subjected to vigorous shaking after each dilution convincingly demonstrate the presence of chemical changes in the composition of aqueous solutions explained by mechanochemical processes. Similar changes were observed in water samples prepared in the same manner with vigorous shaking and dilution without the addition of any chemical compounds. The long-term evolution of the conductivity of such solutions depends on the chemical structure of the solutes.

Physicochemical Study of the Molecular Signal Transfer of Ultra-High Diluted Antibodies to Interferon-Gamma

Physicochemical investigations of (UHD) solutions subjected to certain physical factors (like shaking) are becoming more frequent and increasingly yielding convincing results. A much less studied phenomenon is the transfer of molecular information (UHD signals) from one fluid to another without an intermediate liquid phase. The purpose of this study was to investigate the possibility of such a UHD signal transfer from UHD solutions into the receiver fluid, especially when the molecular source used in solutions was a biologically active molecule of antibodies to interferon-gamma. We used physicochemical measurements and UV spectroscopy for this purpose. The results of this large pilot study confirm the possibility of such a transfer and a rough similarity to the original UHD signal donors, the weaker signal detection relative to the original donor fluids, and that exposure time improves the effect.

Doxorubicin aqueous systems at low concentrations: Interconnection between self-organization, fluorescent and physicochemical properties, and action on hydrobionts

Doxorubicin (Dox) is a highly effective cytostatic antibiotic that exhibits activity against a wide range of malignant neoplasms and is often used as the basis of various anti-tumor compositions. However, the use of Dox in therapeutic doses is associated with high systemic toxicity, which makes it urgent to find ways to reduce therapeutic concentrations, which is necessary primarily to minimize the side effects on the patient's body, as well as to reduce the harmful effects on aquatic ecosystems, commonly polluted by toxic pharmaceuticals. Studying the self-organization, physicochemical and spectral patterns, and their relation to bioeffects of Dox solutions in the range of low concentrations can reveal useful insights into the unknown effects of Dox as a cytostatic and potential pollutant of ecosystems. The self-organization in solutions and on substrates, physicochemical and spectral properties, and action of Dox solutions on hydrobionts were studied in the range of calculated concentrations from 1·10-20 to 1·10-4 M by methods of dynamic and electrophoretic light scattering (DLS and ELS), scanning electron microscopy (SEM), scanning probe microscopy (SPM), fluorescence spectroscopy, UV absorption spectroscopy, conductometry, tensiometry, pH-metry. Certified techniques for monitoring the toxicity of natural water and wastewater were used to establish the interconnection between these phenomena. It was shown that aqueous solutions of Dox are dispersed systems which rearrange their dispersed phase measuring hundreds of nm in size (nanoassociates) at dilution, followed by concerted changes in nanoassociates' parameters (size and ζ-potential) and properties of systems, as well as their bioassay results. SPM and SEM results confirm and complement the DLS and ELS data indicating the existence of nanoassociates in dilute Dox solutions.

L-Tryptophan Aqueous Systems at Low Concentrations: Interconnection between Self-Organization, Fluorescent and Physicochemical Properties, and Action on Hydrobionts

As shown by fluorescence monitoring of dissolved organic matter, amino acid L-Trp can be present in natural water. The consequences of the presence of L-Trp at low concentrations in surface water systems are not yet established for hydrobionts. Studying the physicochemical patterns, as well as their relationships to the bioeffects of L-Trp solutions in the low concentration range, can provide new and important information regarding the unknown effects of L-Trp. The self-organization, physicochemical properties, fluorescence, UV absorption, and action of L-Trp solutions on Paramecium caudatum infusoria, Chlorella vulgaris algae were studied in the calculated concentrations range of 1 × 10⁻²⁰–1 × 10⁻² mol/L. The relationship between these phenomena was established using the certified procedures for monitoring the toxicity of natural water and wastewater. It was shown for the first time that aqueous solutions of L-Trp are dispersed systems in which the dispersed phase (nanoassociates) undergoes a rearrangement with dilution, accompanied by coherent changes in the nanoassociates’ parameters and the properties of systems. The non-monotonic concentration dependence of fluorescence intensity (λ_ex at 225 nm, λ_em at 340 nm) is in good agreement with the data on the nanoassociates’ parameters, as well as with both the physicochemical properties of the systems and their bioassay results.

The Use of Plasmonic Spectroscopy for Detecting Ultra-Low Concentrations of Substances

This paper presents the results of research into the excitation of a surface electromagnetic wave (SEW) in Au/AgI and Au/Ag films contacting aqueous solutions of hydrogen peroxide (H2O2) and sodium chloride (NaCl). The dependences of the SEW excitation angle in the Kretschmann configuration on the interaction time of the solution with the metal film have been obtained. The effect of an aqueous H2O2 solution on the AgI and Ag film under prolonged exposure has been demonstrated. It has been shown that the dynamics of the excitation angle can be used to estimate the concentration of solutions with low and ultra-low concentrations. As an example, the results of using the technique for the analysis of aqueous solutions of NaCl are presented.