The research has been carried out to increase the stability of silver nanoparticles stabilized by maleic acid copolymers in saline and oxidizing media. It is shown that the stability of silver nanoparticles in NaCl and H2O2 solutions increases upon complexation with biocompatible amines, namely, histamine, Lys-OEt, and acetylcholine. The additional steric and electrochemical stabilization allows for maintaining significantly the stability of nanocomplexes in solutions of salts and oxidizing agents at 40 °C. The destruction of the nanocomplexes was studied by UV-vis spectroscopy, transmission electron microscopy, and gel permeation chromatography.

Незважаючи на зниження частоти загострень розсіяного склерозу під час симптом-модифікуючої терапії, проблема лікування рецидивів усе ще актуальна. Кожен рецидив призводить до стійкого неврологічного дефіциту і, отже, до розвитку інвалідизації. Слід зазначити, що внаслідок мінливих даних магнітно-резонансної томографії не завжди можна точно визначити активність хвороби: де­які осередки зникають або зменшуються, в той же час інші з’являються і посилюються. У цьому випадку доцільно використовувати магнітно-резонансну спектроскопію. Магнітно-резонансна спектроскопія допомагає встановити активність захворювання на ранній стадії і визначити біохімічні та нейрофізіологічні ознаки демієлінізації. У статті наведено опис складного клінічного випадку рецидиву розсіяного склерозу і оцінка метаболічної реакції на лікування за допомогою магнітно-резонансної спектроскопії.Таким чином, терапія рецидивів розсіяного склерозу дуже важлива, оскільки дає змогу відстрочити інвалідизацію. Необхідно точно оцінювати всі ризики і переваги кожного типу лікування при рецидивах.

The synthesis of glycoconjugates, lectin-specific polymers containing a carbohydrate ligand (spacered residue of N-acetyl-D-glucosamine, β-N-Gly-GlcNAc) has been carried out. Glyconanoparticles (glycol-NPs) containing a label detectable by means of spectrophotometry, silver nanoparticles, have been prepared on the basis of the glycoconjugates. Copolymers of maleic anhydride with ethylene or N-vinylpyrrolidone have been used as a carrier to introduce the carbohydrate ligand and a stabilizer of silver nanoparticles. Solutions of the glycoconjugates and the silver glyconanoparticles have been characterized by means of light scattering, UV-visible spectroscopy, and TEM. The interaction of the obtained glycoconjugates and silver glyconanoparticles with N-acetyl-D-glucosamine-specific lectins of Solanum tuberosum agglutinin (STA) and wheat germ agglutinin (WGA) has been investigated by means of light scattering and UV-visible spectro-scopy. The data obtained via these physical methods using the carbohydrate-containing derivatives labeled with silver nanoparticles have been in agreement. It has been shown that the glycoconjugates and silver glyconanoparticles based on more hydrophilic copolymer of maleic acid with N-vinylpyrrolidone are more sensitive than the respective systems based on more hydrophobic copolymer of maleic acid with ethylene. It has been also shown that the considered systems are more sensitive to the STA lectin than to the WGA lectin. The silver glyconanoparticles have allowed more accurate and reliable detection of the lectins by means of light scattering, as compared to the glycopolymer.

The complexes of silver ions with furan-2-carboxylic acid (Fur-COOH) and the conjugates of polymer-stabilized silver nanoparticles with silver cations and Fur-COOH are synthesized. The silver nanoparticles are studied by transmission electron microscopy (TEM), while the resulting conjugates—by UV–vis spectroscopy. All the objects obtained display prominent in vitro activity against the H37Rv strain of Mycobacterium tuberculosis. A synergistic effect of the silver components is revealed for the conjugates based on maleic acid-alt-N-vinylpyrrolidone containing nano- and cationic forms of silver, as well as Fur-COOH.

Two spectrophotometric approaches are suggested for the assessment of the concentration of gold(III) cations in an aqueous solution: direct recording of the optical density of gold cations and galvanic substitution of silver atoms in polymer-stabilized silver nanoparticles with gold cations. The sorption capacity of a maleic acid copolymer towards gold cations is estimated. A colloidal composite containing gold nanoparticles is obtained from the polymeric gold salt. The catalytic properties of the resulting polymer-stabilized nanogold are studied in the aerobic oxidation of glucose to gluconic acid.

The specificity of the structure of polymer complexes of silver nanoparticles and silver cations is revealed, and the additive antimicrobial effect of the system components is shown.

In this work, water-soluble polymer composites containing two antimicrobial components, silver nanoparticles and phenol ligands, are obtained. The maleic-acid groups of the used matrix, a copolymer of maleic acid with ethylene, contributed to the production of noncovalent polymer conjugates of p-aminophenol. In addition, they were easily transformed thermally into reactive residues of maleic anhydride, which allowed the synthesis of covalent polymer complexes of p-aminophenol. Silver nanoparticles were obtained via a reduction of the corresponding metal salt with NaBH4 in the presence of phenol-polymer conjugates. The resulting colloidal solutions of preparations were active against a number of opportunistic microorganisms. The minimum inhibitory concentrations were 32 and 64 μg/mL for complex drugs against Escherichia coli, 8 and 16 μg/mL against Pseudomonas aeruginosa, and 4 and 8 μg/mL against Candida albicans for nanosilver-containing noncovalent and covalent polymer complexes of p-aminophenol, respectively. A pronounced synergistic effect of antibacterial components in the used conjugates is revealed in relation to the specified strains of microorganisms; the fractional inhibitory concentration indexes for the obtained composites were less than 0.5.

The design of biologically active dosage forms based on chitosan is significantly limited by its insolubility at pH values above 6.0–6.5 and worsening of its gastrointestinal absorption capacity upon transition to neutral and alkaline environmental conditions. The partial acylation of short-chain chitosans with the use of betaine in the presence of a coupling reagent (betaination) allows one to synthesize noncytotoxic derivatives soluble in an alkaline medium and preserving a high antibacterial activity in weakly alkaline physiological media, which makes them promising for application in pharmaceutical compositions. This study addresses the formation of polyelectrolyte complexes of partially betainated short-chain chitosans with different chain length and degree of betaination with a weak polyacid in acidic and weakly alkaline media. As a polyanion, a regularly alternating copolymer of maleic acid and N-vinylpyrrolidone is used, one of the advantages of which is its ability to be involved in chemical modification with various ligands, including biologically active ones. It is shown that soluble polyelectrolyte complexes can be formed by the direct mixing of components in a weakly alkaline medium (pH 7.4). The range of solubility of the complexes ([polycation] : [polyanion]) in a weakly alkaline medium is wider than that in an acidic one. Nonstoichiometric soluble polyelectrolyte complexes are also prepared using partially betainated chitosans as lyophilizing polyelectrolytes. The structure of soluble polyelectrolyte complexes of various compositions is investigated by static and dynamic light scattering as well as electrophoretic light scattering. The data obtained suggest that, both in the acidic and weakly alkaline medium, the polyelectrolyte complexes occur as polymolecular particles with either negative or positive surface charge. The results of this study can be used for designing new biocompatible and biodegradable delivery systems for biologically active compounds and genetic material.

A method of obtaining multipurpose magnetic chitin, which combines the magnetic properties of magnetite and the adsorption properties of polysaccharide, was proposed. The possibility of using chitin-(CT) and chitosan (CS)-containing magnetic composites for the adsorption of inorganic ions CoII and CrVI and organic substances (2- and 4-nitrophenols) from aqueous media was analyzed. It was shown that the adsorption capacity of magnetic chitin with respect to CoII and CrVI ions reached 41 mg g−1 and 15 mg g−1, respectively. The maximum adsorption capacity for 4-nitrophenol (19 mg g−1 per CT-containing magnetic composite or 56 mg g−1 per chitin component) was about three times higher than for 2-nitrophenol. The obtained adsorbent Fe3O4/CT is environmentally friendly and reusable.

A model of stabilization of spherical silver nanoparticles by amphiphilic macromolecules of a copolymer of ethylene and maleic acid in an aqueous medium based on experimental data previously obtained by transmission electron microscopy and dynamic light scattering is presented. The applicability of various viscometric equations for describing the behavior of a polydisperse system in the course of electrostatic stabilization of nanoparticles is considered. An expression for the relative viscosity of dispersions of spherical silver nanoparticles with an adsorption layer of a copolymer of ethylene and maleic acid in an aqueous medium is obtained. This equation relates the relative viscosity to the chemical structure of the polymer and the molecular weight, concentration, and radius of nanoparticles taking into account the presence of an adsorption polymer layer.

Various types of combinations of amine-containing antibacterial agents (heterocyclic and macrocyclic antibiotics, protein and peptide antibiotics, D-amino acids) and silver nanoparticles stabilized by dicarboxylic (maleic) acid copolymers (AgNPs) are obtained. The study demonstrated the specific action of the conjugates on the planktonic form of gram-positive and gram-negative microorganisms, and fungi. The antimicrobial properties of the conjugates depend on the structures of the AgNPs stabilizing shell, antibacterial agent, and the cell membrane of the pathogen. The polymer shell of the metal nanoparticles allowed to solubilize hydrophobic antibiotics due to the formation of covalent and non-covalent complexes. A pronounced synergistic antimicrobial effect was observed, when AgNPs were combined with hydrophobic amine-containing antibiotics: rifampin—against Staphylococcus aureus and amphotericin B—against Candida albicans. In these cases, the values of Fractional Inhibitory Concentration Indices were lower than 0.5. A pronounced positive bactericidal effect was observed, when using conjugates of AgNPs and a peptide antibiotic (vancomycin) against Enterococcus faecalis, as well as a protein (lysozyme) and D-amino acids against the variety of microorganisms.

A facile and environmentally friendly preparation of a magnetic catalyst for the aerobic oxidation of glucose, combining the properties of two different catalytically active components—gold nanoparticles and glucose oxidase, was developed. This catalyst was synthesized by simple assembly—by sequential deposition of two oppositely charged polymers (chitosan and alternant copolymer of maleic acid) onto the surface of magnetite particles, this outer layer of this interpolyelectrolyte coating contains nanometal and specific enzyme. The catalyst preparation is reproducible and low cost, which uses no toxic reagents, condensing agents, or solvents at all stages. All components of the catalyst are non-toxic; moreover, most of them are the parts of ecosystem. We carried out an effective aerobic oxidation of glucose to gluconic acid using this catalyst. The work offers a new perspective on the production of different hybrid magnetic catalysts.

Methods of synthesizing silver nanoparticles (SNP) of various sizes stabilized with a maleic acid copolymer are proposed. The colloidal solutions of SNP are characterized by electron spectroscopy, static and dynamic light scattering, transmission electron microscopy. The stability of the obtained SNP in solutions of hydrogen peroxide and a hydrochloric acid salt is studied, their efficiency in antimicrobial activity tests is assessed.

Simple technique of preparation of sialolectin-specific nanosilver-labeled colloidal neoglycoconjugates, based on maleic anhydride copolymers and beta-N-glycyl-3'-sialyllactose (SL-AgNPs), was developed. Their physicochemical properties were investigated using TEM, UV-vis-, and H-1-NMR spectroscopy. Interaction of SL-AgNPs with sialic acid specific lectin from Maakia amurensis was studied. Minimum inhibitory concentrations of SL-AgNPs for Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 were also determined. For poly(ethylene-alt-maleic anhydride) based nanocomposite, an additive influence of nanosilver and 3'-sialyllactose on antibacterial activity against Enterococcus faecalis was found.

Multiple sclerosis (MS) develops as a result of an interaction between genetic and environmental factors, among them solar (SA) and geomagnetic activity (GMA) attract the particular attention. An impact of SA and GMA on intrauterine and postnatal period in MS was studied.The study included 358 patients with MS. Correlation (CA) and regression analysis (RA) were used to study the effects of SA and GMA during intrauterine period, the 1st year of life, a year of disease onset, a year before the onset.CA revealed the association between the MS onset and mean values of kp-index in the onset year and the year before the onset year, number of days with kp≥4 and kp≥5 in the onset year and the year before the onset year, mean SFU in the onset year. RA revealed the association between the MS onset and mean kp in the year before the onset year and in the onset year, number of days with kp≥7 in the onset year and the year before the onset year, mean kp during pregnancy, number of days with kp≥7 in the 1st year of life and during pregnancy. The influence of high GMA during pregnancy and in the 1st year of life increases the MS risk in the future and the high GMA predisposes to the MS onset in adults. The practical value of the study is that predicting the GMA changes we can try to prevent the onset and relapses in the risk groups.

Silver nanoparticles have been prepared by the reduction of the corresponding metal salt with NaBH 4 in the presence of appropriate dispersing agents, namely, copolymers of maleic acid with N-vinylpyrrolidone, ethylene and styrene or their amphyphi- lic derivative containing octadecylamide ligands. The silver colloids identified by optical absorption spectroscopy were synthesized when the copolymer concentrations were lower than their critical aggregation concentrations and copolymer/Ag+ molar ratio no greater than a unit. According to the data of transmission electron microscopy, the obtained Ag nanoparticles were spherical-shaped particles 1—2 nm in size. Colloidal solutions of the prepared nanosilver showed a strong inhibiting antifungal activity against a fungal plant pathogen Fusarium oxysporum and also Gram-negative, Gram-positive bacteria and yeast. The silver nanoparticles stabilized with more hydrophilic compounds from among the investigated copolymers demonstrated the higher antibacterial and antifungal activity.