Carboxymethylcellulose Sodium Salt Research Articles

Особенности термоагрегации бычьего сывороточного альбумина в присутствии сильных полиэлектролитов

The influence of temperature on bovine serum albumin (BSA) aggregation in aqueous solutions in the presence of poly-N,N-dimethyl-N,N-diallylammonium chloride (PDMDAAC) and the sodium salt of carboxymethylcellulose (CMC) was studied. It was shown that protein-polyelectrolyte complexes (PPC) form because of macromolecular reactions that are stabilized mainly by electrostatic forces. To characterize the PPC composition the φ parameter was used. This parameter is defined as the ratio of the concentration of ionic groups of polyelectrolyte per protein molecules. It was studied that when in an interpolyelectrolyte reaction, a sufficiently high degree of transformation occurs the polymer electrolyte initiates aggregation of protein molecules. As the temperature increases, the initiating role of the polymer electrolyte increases due to an increase in the intensity of hydrophobic interactions. Using the method of spectrophotometry, it was found that, depending on the nature of the polymer electrolyte, insoluble complexes of bovine serum albumin are formed when the pH parameter is above or below the isoelectric point of the protein, when its macromolecules are negatively or positively charged. In the presence of poly-N,N-dimethyl-N,N-diallylammonium chloride, the intensive formation of aggregates and their rapid precipitation in the form of flakes at pH > 7.0 was observed when the temperature increased to 60 °C. The maximum yield of the product of the interpolyelectrolyte reaction bovine serum albumin – sodium salt of carboxymethylcellulose was detected at pH ≤ 4.0. A temperature increase up to 60 °C, in this case, was not accompanied by intensive flocculation. Under optimal composition and interaction conditions, the degree of transformation in the BSA – PDMDAAX and BSA – CMC reactions is ~0.93 and 0.9, respectively, and decreases by ~5-7% with an increase in temperature to 60 °C. It was shown that for the same BOD composition (the ratio of components in the [CMC]/[BSA] complex = 0.1 g/g), an increase in temperature from 25 to 60 °C leads to the formation of particles that increase in size from 1 mcm to 5 mcm. The temperature increase leads to a change in composition of BOD, corresponding to its maximum output as a interpolyelectrolyte reactions product: for complex with PDMDAAC at T = 25, 40 and 60 °C, the φ value is 70, 60, 15; for the complex with the CMC – 60, 50, 20.

ИННОВАЦИОННЫЕ ПОДХОДЫ В ПРИМЕНЕНИИ ПОЛИМЕРНЫХ ПРЕПАРАТОВ НА ОСНОВЕ ХИТОЗАНА В АГРОПРОМЫШЛЕННОМ КОМПЛЕКСЕ

The study proposes an innovative technology of presowing treatment of seeds of agricultural crops, in particular, the encapsulation of an environmentally friendly domestic polymer preparation based on chitosan obtained from silkworm pupae. The UZChITAN preparation for seed encapsulation was developed and the effective molecular weight characteristics of chitosan for its production with improved performance properties were investigated, and the values of its optimal molecular weight of at least 70,000 and the degree of deacetylation of at least 60% have been revealed. It was experimentally confirmed that the sodium salt of carboxymethyl cellulose with a degree of polymerization of 500-750 and a degree of substitution of 0.8-1.0 provides the biological activity of the UZChITAN preparation. The drug has been tested in various cultivation zones; it contributes to an increase in germination energy, depending on crops, up to 10%, as well as the germination rate up to 20%. UZChITAN is included in the list of pesticides and agrochemicals approved for use in agriculture of the Republic of Uzbekistan.

Heterologous expression and biochemical characterization of a thermostable endo-β-1,4-glucanase from Colletotrichum orchidophilum.

To develop new cellulases for efficient utilization of the lignocellulose, an endoglucanase (CoCel5A) gene from Colletotrichum orchidophilum was synthesized and a recombinant Pichia pastoris GS115/pPIC9K/cocel5A was constructed for secretory expression of CoCel5A. After purification, the protein CoCel5A was biochemically characterized. The endoglucanase CoCel5A exhibited the optimal activity at 55-75°C and high thermostability (about 85% residual activity) at the temperature of 55°C after incubation for 3h. The highest activity of CoCel5A was detected when 100mM citric acid buffer (pH 4.0-5.0) was used and excellent pH stability (up to 95% residual activity) was observed after incubation in 100mM citric acid buffer (pH 3.0-6.0) at 4°C for 24h. Carboxymethyl cellulose sodium salt (n = approx. 500) (CMC) and β-D-glucan were the best substrates for CoCel5A among the tested substrates. The kinetic parameters Vmax, Km, and Kcat/Km values against CMC were 290.70U/mg, 2.65mg/mL, and 75.67mL/mg/s, respectively; and 228.31U/mg, 2.06mg/mL, and 76.45mL/mg/s against β-D-glucan, respectively, suggesting that CoCel5A has high affinity and catalytic efficiency. These properties supported the potential application of CoCel5A in biotechnological and environmental fields.

Characterization of an alkali-tolerant, thermostable, and multifunctional GH5 family endoglucanase from Thermoactinospora rubra YIM 77501T for prebiotic production

A novel endoglucanase gene (1425 bp), designated thrcel5A, was cloned from Thermoactinospora rubra YIM 77501Tand determined to be a member of glycoside hydrolase family 5. The putative amino acid sequence displayed 76% conservation with reported endoglucanases (GenBank: SCG57304.1) from Micromonospora siamensis. Thrcel5A was expressed in Escherichia coli BL 21 (DE3) and purified using Ni2+-affinity chromatography. The resulting purified protein displayed high hydrolytic activity against the sodium salt of carboxymethyl cellulose and β-(1, 3; 1, 4)-glucans from barley and beechwood xylan, with specific activities of 85.7 ± 1.5, 120.3 ± 2.6, and 22.9 ± 1.1 U/mg, respectively. The optimal pH and temperature for the recombinant enzyme were determined to be 8.5 and 60 °C, respectively. Additionally, ThrCel5A was thermotolerant as it retained more than 60% of its original activity after an incubation at 60 °C for 2 h. Moreover, ThrCel5A can hydrolyze β-(1, 3; 1, 4)-glucan into prebiotics, such as cellobiose, cellotriose, and cellotetrose. Its endoglucanase activity was significantly affected by link sequences and CBM2. Due to being an alkali-tolerant, thermostable, and multifunctional cellulolytic enzyme, ThrCel5A is an attractive candidate for use in production of prebiotics.

Selection of excipients for the purpose of creating an intranasal gel of interleukin-1 receptor antagonist β (IL-1ra)

There is a negative dynamic of the spread of cerebrovascular diseases, which often lead to disability or death in patients in the world, today. Such diseases are characterized by acute disorders of cerebral metabolism and blood circulation, against the background of other chronic pathologies. More than one hundred thousand cases of stroke are registered in Ukraine every year, with more than thirty percent of patients dying within the first month of the disease according to the Center for Medical Statistics of the Ministry of Health of Ukraine. The nasal route of administration is a promising method of transporting active substances for systemic action, various pharmacotherapeutic groups, both small and large molecules. The created nasal preparations of hormones, antibiotics, analgesics, exhibit a quick therapeutic effect due to the branched capillary system in the nasal cavity. In addition, the nasal route of administration is the most promising non-invasive method for delivering active substances to the brain for cerebroprotective drugs, due to the anatomical features of the location of the nerves. According to published data, the researchers found that the receptor antagonist of interleukin-1 (IL-1ra) exhibits neuroprotective properties in brain ischemia by blocking excess IL-1 and activating the anti-inflammatory cytokine cascade, in order to reduce local inflammation and neuronal loss. Therefore, in order to expand the range of pharmacotherapeutic drugs – neuroprotectors, the development of a new intranasal form with the active pharmaceutical ingredient - receptor antagonist interleukin-1 (IL-1ra) is an urgent problem of modern medicine and pharmacy. The aim of work was to substantiate the choice of excipients for the new intranasal gel of the receptor antagonist of interleukin-1 (IL-1ra). Materials and methods. The studies were carried out according to the plan of two-way analysis of variance with repeated observations. Factors that were investigated: factor A (type of polymer) – A1 – chitosan 3 %, A2 – sodium carboxymethyl cellulose 0.3 %, A3 – sodium hyaluronate 0.7 %, A4 – sodium alginate 0.5 %; factor B (type of alcohol): B1 – without alcohol, B2 – sorbitol, B3 – glycerin, B4 – D-panthenol. A prefabricated solution of the receptor antagonist of interleukin-1 (IL-1ra) was used as an active substance. A portion of the active substance was taken considering the calculations, to ensure a concentration of 0.5 % IL-1ra in each composition. The release of the active pharmaceutical ingredient was determined by equilibrium dialysis according to Kruvchinsky at 37.0 ± 0.5 °C through a semi-permeable membrane – “Cuprofan” for all compositions. Dialysis was performed in Franz cells at a nine-position station (PermeGear, Inc., USA). The concentration of IL-1ra, after 30 minutes, was determined by UV spectrophotometry at a wavelength of 280 nm on a UV-2600 spectrophotometer (Shimadzu Corporation, Japan). Results. We studied the effect of pharmaceutical factors (polymers and alcohols) on the intensity of the release of IL-1ra from the nasal form to justify the choice of excipients for the nasal gel of the receptor antagonist interleukin-1 β. The results of the analysis of variance of pharmaceutical factors (polymers and alcohols) showed that hydrophilic polymers and humectants had a significant effect on the release of the active substance from the experimental compositions. It is advisable to use a mucoadhesive polymer – sodium salt of carboxymethylcellulose, as well as alcohol-moisturizer D-panthenol for the new nasal form of IL-1ra, as excipients. Conclusions . Excipients were selected for a liquid intranasal gel with the receptor antagonist interleukin-1 (IL-1ra). It was found that the type of mucoadhesive polymers and alcohols, to moisten the mucous membrane, had a significant effect on the release of the active pharmaceutical ingredient from nasal dosage forms. As a result of research, it was found that the optimal release of IL-1ra from nasal compositions was provided by excipients - hydrophilic mucoadhesive component - sodium carboxymethylcellulose with the addition of humectant alcohol – D-panthenol.

Tixotropic Properties of Solutions of Some Polysaccharides

The thixotropic properties of aqueous solutions of the following polysaccharides are studied: chitosan, its water-soluble derivative the sodium salt of chitosan succinamide, and the sodium salt of carboxymethyl cellulose. These polymers have been selected due to their physiological activity and the possibility of using them for biomedical purposes. Studying the effect of the polymer concentration on rheological behavior shows that if a dilute polysaccharide solution is taken for research, then the flow curve does not actually depend on the time of exposure to the shear strain; i.e., the system is thixostable and in equilibrium, in contrast to semidiluted solutions, which clearly demonstrate nonequilibrium and thixotropy. The solutions of the studied polysaccharides behave like thixotropic systems only in the concentration region where supramolecular structures are uniquely formed and the time required for their destruction is comparable with the experiment’s time.

Rheological Properties and Water-Retaining Power of Agar Hydrogels with Carboxymethyl Cellulose

Rheological properties of composite hydrogels of agar with carboxymethyl cellulose sodium salt (NaCMC), intended for water conservation, were studied. The viscosity and yield stress of the hydrogels can both increase and decrease depending on the ratio of the polymer components in the hydrogel. Heating of the starting mixture for hydrogel preparation in the magnetic field influences the rheological properties of both agar and composite hydrogels. The stability of the hydrogels in storage and the syneresis depend on the NaCMC to agar ratio. The total water loss by the hydrogel samples in 1 year does not exceed 2 wt %. Introduction of NaCMC prevents syneresis in the course of the hydrogel freezing–thawing.

Preparation of Sodium Carboxymethly Cellulose Hydrogel for Controlled Release of Manganese Micronutrient

In order to use potential in the development of wheatgrass plant (Triticum Aestivum), carboxymethyl cellulose sodium salt (NaCMC) hydrogels were prepared. The characterization of synthesized hydrogels was examined. Water absorbency and gel content properties were influenced the amount of crosslinker in hydrogels. The water absorbency was negatively affected with crosslinker on the contrary gel content. The application of hydrogels improved the water retention capacity of soil. The manganese release was examined in water and soil and the release slowed down with crosslinker. Manganese-loaded hydrogels were used for growing the wheatgrass plant. The growing of plant was positively affected with using manganese-loaded hydrogels. These results suggest that manganese-loaded hydrogels could be utilized as a controlled fertilizer system in agriculture areas.

Role of glycine 256 residue in improving the catalytic efficiency of mutant endoglucanase of family 5 glycoside hydrolase from Bacillus amyloliquefaciens SS35.

Wild-type, BaGH5-WT and mutant, BaGH5-UV2 (aspartate residue mutated to glycine), endoglucanases belonging to glycoside hydrolase family 5 (GH5), from wild-type, and UV2 mutant strain of Bacillus amyloliquefaciens SS35, respectively, were earlier cloned in pHTP0 cloning vector. In this study, genes encoding BaGH5-WT or BaGH5-UV2 were cloned into pET28a(+) expression-vector and expressed in Escherichia coli BL-21(DE3)pLysS cells. BaGH5-UV2 showed 10-fold (43.6 U/mg) higher specific activity against carboxymethylcellulose sodium salt (CMC-Na), higher optimal temperature by 10°C at 65°C, and 22-fold higher catalytic efficiency against CMC-Na, than BaGH5-WT. BaGH5-UV2 showed stability in wider acidic pH range (5.0-7.0) unlike BaGH5-WT in narrow basic pH range (7.0-7.5). BaGH5-UV2 displayed a mutation, Asp256Gly in L11 loop, connecting β6 -sheet with α6 -helix, near active site toward the domain surface of (α/β)8 -TIM barrel fold. Molecular dynamics simulation studies showed more stable structure, accessibility of substrate for a catalytic site, and increased flexibility of loop L11 of BaGH5-UV2 than the wild type, suggesting enhanced catalysis by BaGH5-UV2. Molecular docking analysis displayed enhanced hydrogen bond interactions of cello-oligosaccharides with BaGH5-UV2, unlike BaGH5-WT. Thus, Gly256 residue of loop L11 plays an important role in enhancing catalytic efficiency, and pH stability of GH5 endoglucanase. Therefore, these results help in protein engineering of GH5 endoglucanase for improved biochemical properties.

New methods of local medical treatment of purulent wounds

Purpose of the study. To study experimental model of purulent wounds efficiency of the combined effects of benzalkonium chloride and metronidazole immobilized on various bases.Materials and methods. The material was in vitro studies and experimental animals (Wistar rats), which was modeled a purulent wound and then divided into 3 groups according to the treatment method with the three studied combinations, each of which contained benzalkonium chloride and metronidazole, the combinations differed in bases, which were polyethylene oxide or sodium salt of carboxymethylcellulose, or polymethylsiloxane polyhydrate. Research methods: in an in vitro experiment, growth retardation zones were determined for the most common pathogens of wound infection using the standard disc method. In an in vivo experiment the healing process was evaluated by Popov's planimetric method, the contamination of the wounds was studied by sowing the biopsy of wounds on nutrient media with subsequent counting of the grown up colonies. The data were processed statistically, the reliability of the differences was assessed by the Kruskal-Wallis test.Results. All test combinations showed high growth retardation areas for all test strains of microorganisms. Objectively, the highest results were observed with a combination of polyethylene oxide (Staphylococcus aureus 30 (29; 30), Bacillus cereus 27 (27; 28), Escherichia coli 20.5 (20; 21), Proteus vulgaris 21.5 (20; 22), Pseudomonas aeruginosa 17 (16; 17), Candida albicans 25.5 (25; 26)). In determining the healing rate, it was noted that the maximum values in the groups when using combinations based on the sodium salt of carboxymethylcellulose and polymethylsiloxane polyhydrate occurred on day 1–3 (29.6 (27.6; 31) and 20.2 (18.8; 24.2) mm2/day, respectively), and in the group using a combination on polyethylene oxide — for 3–5 days (20.6 (17.3; 22.8) mm2/day).Conclusion. Our studies have shown the high antimicrobial activity of all the developed combinations for all the strains of microorganisms studied. It is also possible to recommend combinations on polyethylene oxide and sodium salt of carboxymethylcellulose for further preclinical studies at all times of treatment, and a combination based on polymethylsiloxane polyhydrate only in the first phase of the wound process.

Synthesis of graft copolymers of carboxymethyl cellulose and N,N-dimethylaminoethyl methacrylate and their study as Paclitaxel carriers

The double-sensitive graft copolymers of sodium salt of carboxymethyl cellulose (Na-CMC) and N,N-dimethylaminoethyl methacrylate (DMAEMA) with different content are successfully synthesized by radical polymerization applying a redox initiator. Aqueous solution of the synthesized copolymers has a lower critical solution temperature (LCST) in the range of 37–44 °C, and the sizes of copolymer particles being multichain spherical negative-charged aggregates are in a 118–133 nm range. Na-CMC-g-PDMAEMA copolymer particles are stable in a 0.15 N NaCl aqueous solution and in the physiological pH range, which allows to apply them as vectors for targeted drug delivery. Conjugation between Paclitaxel (Ptx) and Na-CMC-g-PDMAEMA copolymer is due to hydrophobic and electrostatic interaction between functional groups of each component; copolymers are characterized by relatively high values of loading and encapsulation efficiencies of Ptx. In vitro release kinetics was also researched in acidic and neutral media at 38 °C. The release process of Ptx from a copolymer conjugate is described by Korsmeyer–Peppas kinetic model and limited by molecular diffusion.

The use of mucilage extracted from Opuntia ficus indica as a microencapsulating shell

This study was aimed at investigating the micro-formulation of capsules using natural biopolymers, such as cactus mucilage (CM), carboxymethyl cellulose sodium salt (CMCNa) and chitosan (Chi) as the wall material, for the transport and supply of sunflower oil. CM samples were extracted from Opuntia ficus indica (OFI) by precipitation at different supernatant pH values (2, 4 and 12). The extracted natural polysaccharide and the resulting microcapsules were characterized by different experimental techniques. Fourier transform infrared spectroscopy analysis of the CM showed the presence of uronic acid units and sugars. Scanning electron microscopy revealed that most particles were adhered together, causing the formation of compact, linked agglomerates, which resulted in different microstructures with irregular shapes. All oil?core microcapsules were characterized, and the results showed that the different shell materials could be used to microencapsulate sunflower oil. Among them, the microcapsule crosslinked with CM and Chi was the most suitable, with the highest encapsulation efficiency (95 %). This coacervation led to the narrowest size distribution of the capsules, with diameters ranging from 1 to 5 ?m. Optical microscopy confirmed the deposition of coacervate droplets around oil drops and clearly showed that the formation of coacervated particles and their deposition onto oil droplets were successive events.

Изучение физико-химических свойств материалов на основе полимерных комплексов некоторых водорастворимых полимеров

Polymer complexes based on water-soluble physiologically-neutral polymers are promising for creating biomedical materials used in targeted delivery systems of drugs, enzymes or genes, as well as for encapsulating biological substances in biomedicine. In this work, the creation of film materials based on polymer complexes has used the sodium salt of succinyl chitosan, polyvinylpyrrolidone, sodium salt of carboxymethylcellulose, polyethylene glycol. Polyvinylpyrrolidone and polyethylene glycol are characterized by unsatisfactory a film-forming and gel-forming property, which limits their application in medical practice. These shortcomings have been compensated by the introduction of polysaccharides. It has been shown that the variation in composition of the studied polymer complexes allows changing purposefully the hydrophilic-hydrophobic balance of the surface and sorption properties of polymer films based on them. The preparation of polymer complexes consisted of adding a portion of poly-N-vinylpyrrolidone or polyethylene glycol to solutions of the sodium salt of succinyl chitosan or sodium salt of carboxymethylcellulose so that the ratio of the components of the complex was equimolar. Films based on polymer complexes were prepared by the method of pouring solutions of polymer mixtures with a concentration of 1 mol/L onto a previously defatted surface of a Petri dish. The thickness of the film samples was maintained constant and equal to 0.1 mm. It was shown that the preparation of polymer complexes of the sodium salt of chitosan succinyl or the sodium salt of carboxymethyl cellulose with poly-(N-vinylpyrrolidone) or polyethylene glycol allows one to purposefully change the hydrophilic-hydrophobic balance of the surface of polymer films based on them. Also, film materials based on the studied polymer complexes have satisfactory sorption properties for water vapor. These facts suggest that systems based on polymer complexes of the sodium salt of chitosan succinyl or sodium salt of carboxymethylcellulose with poly (N-vinyl pyrrolidone) or polyethylene glycol can serve as the basis for the creation of film or gel polymer materials for medical use.

Amnion and collagen-based blended hydrogel improves burn healing efficacy on a rat skin wound model in the presence of wound dressing biomembrane.

A burn wound is one of the most frequent and devastating injuries for patients which requires extensive care. Early treatment of burn wounds improves healing significantly. This study was designed to investigate the efficacy of amnion and collagen-based hydrogels on cutaneous burn wound healing in rats with covering membrane. We prepared a novel cell free hydrogel comprising human amnion, rabbit collagen, carboxymethyl cellulose sodium salt, citric acid, methyl paraben, propyl paraben, glycerin and triethanol amine. The wound covering membrane was developed from rabbit collagen and prawn shell chitosan. Beside swelling ratio, water absorption, equilibrium water content, gel fraction and spreadability analysis, in vitro cytotoxicity and biocompatibility tests were performed for the formulated hydrogels. Following the skin irritation study, second-degree burns were created on the dorsal region of the rats and the gels were applied with/without covering membrane to study the wound contraction and re-epithelialization period. The formulated hydrogels were observed non-cytotoxic and compatible with human blood cells. No erythema and edema were found in skin irritation assay confirming the safety and applicability. Hydrogel consisting in a combination of amnion and collagen demonstrated significantly rapid wound healing, driven by complete re-epithelialization (16.75 ± 0.96 days) and closure by wound contraction (72 ± 3.27%, P < 0.0000009) when wound dressing membrane was used, whereas this gel alone healed about 62.5 ± 4.43% (P < 0.00001) and required 18.75 ± 0.50 days to complete re-epithelialization. Additionally, the gel with covering membrane treated group had maximum average body weight, food and water intake. The amnion and collagen-based blended gel offers alternative possibilities to treat skin wounds when covered with film, which could overcome the limitations associated with modern therapeutic products such as high costs, long manufacturing times, complexities, storing, and presence of living biomaterials.

Application of Рolyelectrolyte Сomplexes for the Removal of Suspended Particles in the Process of Water Treatment аnd Рurification

The possibility and efficiency of biflocсulation systems, including polymer electrolytes capable of interaction and polyelectrolyte complexes formation, usage in the processes of water treatment for the mineral particles separation, was studied. The influence of the nature, molecular weight of polyelectrolyte components and their ratio in the system on the efficiency and speed of the dispersed phase particles deposition process was considered. Sodium salt of carboxymethylcellulose, poly-N,N-dimethyl-N,N-diallylammonium chloride and polyanions and polycations polyacrylamide-based were used as polyelectrolytes. It was shown that application biflocсulation systems significantly increases the speed of the dispersed phase separation and allows to improve the clarification quality of the dispersion with a much lower (compared to monoflocculation systems) consumption of polymer electrolytes.

Inhibitors based on new polysaccharides in technological processes of oil production. Efficiency of inhibition of scale formation and influence on stability of water-oil emulsion

Functionalized nitrogen-containing polysaccharides based on available low molecular weight sample of carboxymethylcellulose (CMC) with a molecular mass of 90 thousand and mono-, di- and tri- ethanolamine were obtained. The study of CMC salts with ethanolamine as inhibitors of salt deposition was carried out at 80 °C by capillary testing. It was shown that at the concentration of 10-30 mg/l these salts inhibit the processes of scale deposition of CaCO3 and their efficiency is 53-80%. Rheological and sedimentation characteristics of artificially obtained water-oil (w/o) emulsions based on oil of the Priobskoye oilfield without and in the presence of low molecular weight sodium salt of carboxymethylcellulose (NaCMC) were studied. It was found that the NaCMC does not increase the viscosity and stability of W/O emulsions at concentrations of 50, 100, 200 mg/l.

Smart Binders for Silicon Based Composite Electrode in Li-Ion Batteries

Silicon is one of the most promising alloying anode materials for Li-ion batteries thanks to its high specific and volumetric capacity. In comparison with the commercially available graphite, silicon delivers 10 times higher specific capacity (up to 3600 mA.h.g-1) and 3 times higher volumetric capacity ( up to 2200 mA.h.cm-3) [1]. However, silicon suffers from high volumic expansion upon lithiation (up to 280 %). It induces the pulverization of the micrometric silicon particle, the perpetual solid electrolyte interface renewal and decohesion between constitutive elements of the electrode, drastically reducing its lifespan [2].To tackle those issues we propose the formulation of composite electrode with improved binder. It is composed of carboxymethyl cellulose sodium salt (NaCMC, as a binding network) and zinc sulfate dissolved in a pH 3 buffer solution (composed of citric acid and potassium hydroxide). The originality and improvement comes from the use Zn2+ ions as coordination agents, binding to carboxylate groups from the CMC and citric acid. Among benefits, we believe that the coordination helps to mitigate the stress inside the electrode because of the improved reticulation of the network, thus improving its resilience [3]. To support this hypothesis, we provide physico-chemical characterizations of the binder as well as the electrochemical performances of our electrodes. [1] M.N. Obrovac, V.L. Chevrier, Alloy Negative Electrodes for Li-Ion Batteries. Chem. Rev. 2014, 114, 11444-11502. [2] A. Etiemble, A. Tranchot, T. Douillard, H. Idrissi, E. Maire, L. Roué., Evolution of the 3D Microstructure of a Si-Based Electrode for Li-Ion Batteries Investigated by FIB/SEM Tomography, J. Electrochem. Soc. 2016,163, A1550-A1559 [3] D. Mazouzi, R. Grissa, M. Paris, Z. Karkar, L. Huet, D. Guyomard, L. Roué, T. Devic, B. Lestriez, CMC-citric acid Cu(II) cross-linked binder approach to improve the electrochemical performance of Si-based electrodes. Electrochim. Acta 2019, 304, 495-504.

Features of the Hydrolysis Kinetics of Micrococcus lysodeikticus by Immobilized Lysozyme

Background. The problem of the resistance of bacterial pathogens to antibiotics leads to a decrease in the effectiveness of therapy of infectious diseases, which in turn stimulates the search, modification or creation of new antibacterial agents, including lysozyme-polymer systems. The development of new biotechnological preparations of the enzyme with mucoadhesive properties, antimicrobial action, in the form of gels, hydrogel coatings or films, promising for use in medicine, is impossible without understanding the lysozyme functioning in an immobilized state. Therefore, studying the kinetic features of substrate hydrolysis by free and immobilized lysozyme, comparing the kinetic parameters of various forms of the enzyme is an urgent task. Objective. The aim of the paper is to study the kinetics of hydrolysis of Micrococcus lysodeikticus cells with lysozyme immobilized into gelatin, carboxymethyl cellulose sodium salt, and polyvinyl alcohol, as well as to compare kinetic characteristics with the parameters of the free enzyme. Methods. Immobilization of lysozyme into gelatin, sodium salt of carboxymethyl cellulose, polyvinyl alcohol was carried out by incorporation into a gel. The kinetic parameters of the functioning of the enzyme were determined by the initial lysis rates of M . lysodeikticus cells. The measurement results were analyzed using the Linuiver–Burke's and Haines' graphical methods, as well as the Cornish-Bowden–Eisenthal's computational method. Results. Kinetic features of the hydrolysis reaction of M . lysodeikticus cells by free and immobilized lysozyme were studied. The increase in Michaelis constant K M , the maximum reaction rate V max and the ratio K M / V max for the immobilized enzyme was shown. The tendency to increase the values of kinetic parameters is preserved both using the graphical linearization methods of Lineuiver–Burke and Haines and the Cornish-Bowden–Eisenthal's computational method, which is manifested in the transitional activation of lysozyme. In turn, a decrease in k cat / K M indicates a decrease in the rate of binding of the immobilized enzyme to the substrate. Conclusions. As a result of studying the kinetics of hydrolysis by three methods, it was shown that the action of the studied polymers (gelatin, sodium salt of carboxymethyl cellulose, and polyvinyl alcohol) is kinetically manifested in the transitional activation of the enzyme, according to the pattern of peptidoglycan of the cell wall of M . lysodeikticus . It has been revealed that the catalytic efficiency of lysozyme is most affected by the sodium salt of carboxymethyl cellulose, decreasing it by 37.8%, while gelatin and polyvinyl alcohol decrease this parameter by 31.8 and 18.8%, respectively. The results of the study are of fundamental and applied value, since they complement knowledge of the kinetic features of the functioning of immobilized forms of lysozyme, the interaction of the enzyme with polymers, and allow us to evaluate the catalytic efficiency of the obtained biotechnological products.

Hydrogel-Polymer Electrolyte for Electrochemical Capacitors with High Volumetric Energy and Life Span.

AC/AC (AC=activated carbon) electrochemical capacitors (ECs) were designed with a 1 mol L-1 lithium sulfate hydrogel- polymer electrolyte (HPE) based on carboxymethyl cellulose sodium salt (CMC). The electrochemical performance of the ECs was compared with that of cells composed of common separators such as a polyolefin membrane (Celgard 3501, polypropylene separator coated by surfactant) and a glass microfiber membrane (Whatman GF/A). The ECs with Celgard 3501 and home-made CMC-HPE demonstrated a higher volumetric energy than that with Whatman GF/A. However, after 120 h of floating at 1.5 V, the capacitance of the EC with Celgard 3501 decreased dramatically by 25 %, whereas with CMC-HPE and Whatman GF/A, the decrease was only 4 and 6 %, respectively. Post-mortem observations of the Celgard 3501 separator after floating suggested that the surfactant layer was removed, which caused a decrease of separator wettability, as confirmed by the slow evolution of the electrolyte contact angle on its surface. Hence, CMC-HPE is a very attractive option to develop aqueous-electrolyte-based ECs with an excellent life span and high volumetric energy density.

Hybrid nanocomposites of carboxymethyl cellulose cross-linked by in-situ formed Cu2O nanoparticles for photocatalytic applications

A one-step on air synthesis of water-soluble composites from carboxymethylcellulose sodium salt (CMC) and Cu2O nanoparticles, ca. 10 nm in diameter is described. The polymer matrix stabilizes the nanoparticles against aggregation via electrostatic interaction between carboxyl groups of the polymer and Cu(1+)-ions on the nanoparticle surface. Being dispersed in water, the composites initiate a photocatalytic oxidation of an azo dye Methyl Orange. The oxidation proceeds in the presence of oxygen and accelerates significantly up to a 100 conversion when hydrogen peroxide is added. The Cu2O-CMC composites have potential for photochemical decomposition of organic contaminants in water waste.