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The poly(vinyl alcohol) (PVA) physical cryogels that contained the additives of the H2N-(CH2)n-COOH–type amino acids (n = 1–5) have been prepared, and their physico-chemical characteristics, macroporous morphology and the solute release dynamics have been evaluated. These low-molecular solutes with respect of the PVA cryotropic gelation exhibited the kosmotropic influence, i.e. commencing from their concentration of about 0.5 mol/L the additives facilitated the growth in the rigidity and the heat endurance of the resultant cryogels. The efficiency of such influence was reduced with an increase in the length of oligomethylene spacer between the amino and carboxyl groups in the amino acid molecules. The average size of macropores also depended on the additive type and its concentration in the initial PVA solution; the cross-section of the pores decreased with increasing the solutes concentration. Upon the cryogel-entrapped amino acids release from the macroporous gel matrix a gradual transition from the release mechanism by a free diffusion for the hydrophilic glycine to the release according to the space-limited Fickian diffusion for the more hydrophobic ε-aminocaproic acid was found. This effect was stipulated by the hydrophobic interactions between the carbochain core of the PVA macromolecules and the aliphatic moieties of the respective amino acid.
Olga Yu. Kolosova; Polina A. Karelina; Viktor G. Vasil'Ev; Valerij Ya. Grinberg; Ilya I. Kurochkin; Vladimir I. Lozinsky. Cryostructuring of polymeric systems. 58. Influence of the H2N-(CH2) -COOH–type amino acid additives on formation, properties, microstructure and drug release behaviour of poly(vinyl alcohol) cryogels. Reactive and Functional Polymers 2021, 167, 105010 .
AMA StyleOlga Yu. Kolosova, Polina A. Karelina, Viktor G. Vasil'Ev, Valerij Ya. Grinberg, Ilya I. Kurochkin, Vladimir I. Lozinsky. Cryostructuring of polymeric systems. 58. Influence of the H2N-(CH2) -COOH–type amino acid additives on formation, properties, microstructure and drug release behaviour of poly(vinyl alcohol) cryogels. Reactive and Functional Polymers. 2021; 167 ():105010.
Chicago/Turabian StyleOlga Yu. Kolosova; Polina A. Karelina; Viktor G. Vasil'Ev; Valerij Ya. Grinberg; Ilya I. Kurochkin; Vladimir I. Lozinsky. 2021. "Cryostructuring of polymeric systems. 58. Influence of the H2N-(CH2) -COOH–type amino acid additives on formation, properties, microstructure and drug release behaviour of poly(vinyl alcohol) cryogels." Reactive and Functional Polymers 167, no. : 105010.
Wide-pore proteinaceous freeze–thaw spongy gels were synthesized via the cryotropic gelation technique using the bovine blood serum or its diluted solutions as the protein-containing precursors. The feed systems also included the denaturant (urea) and the thiol-reductant (cysteine). The gel-fraction yield decreased and the swelling degree of the walls of macropores in such heterophase matrices increased with decreasing the initial protein concentration. The optimum freezing temperature was found to be within a rather narrow range from −15 to −20 °C. In this case, the average size of the macropores in the resultant cryogels was 90–110 μm. The suitability of such soft wide-pore gel materials for the application as the carriers of peptide bioregulators was demonstrated in the in vitro experiments, when the posterior segments of the Pleurodeles waltl adult newts’ eyes were used as a model biological target. It was shown that a statistically reliable protective effect on the state of the sclera, vascular membrane and retinal pigment epithelium, as well as on the viability of fibroblasts, was inherent in the proteinaceous cryogels loaded with the peptide bioregulator (Viophtan-5™) isolated from the bovine eye sclera.
Egor V. Sidorskii; Mikhail S. Krasnov; Viktoria P. Yamskova; Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems: 57 Spongy Wide-Porous Cryogels Based on the Proteins of Blood Serum: Preparation, Properties and Application as the Carriers of Peptide Bioregulators. Gels 2020, 6, 50 .
AMA StyleEgor V. Sidorskii, Mikhail S. Krasnov, Viktoria P. Yamskova, Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems: 57 Spongy Wide-Porous Cryogels Based on the Proteins of Blood Serum: Preparation, Properties and Application as the Carriers of Peptide Bioregulators. Gels. 2020; 6 (4):50.
Chicago/Turabian StyleEgor V. Sidorskii; Mikhail S. Krasnov; Viktoria P. Yamskova; Vladimir I. Lozinsky. 2020. "Cryostructuring of Polymeric Systems: 57 Spongy Wide-Porous Cryogels Based on the Proteins of Blood Serum: Preparation, Properties and Application as the Carriers of Peptide Bioregulators." Gels 6, no. 4: 50.
Recent studies undoubtedly show that the mammalian target of rapamycin (mTOR) and the Hippo–Yes-associated protein 1 (YAP) pathways are important mediators of mechanical cues. The crosstalk between these pathways as well as de-regulation of their signaling has been implicated in multiple tumor types, including liver tumors. Additionally, physical cues from 3D microenvironments have been identified to alter gene expression and differentiation of different cell lineages. However, it remains incompletely understood how physical constraints originated in 3D cultures affect cell plasticity and what the key mediators are of such process. In this work, we use collagen scaffolds as a model of a soft 3D microenvironment to alter cellular size and study the mechanotransduction that regulates that process. We show that the YAP-mTOR axis is a downstream effector of 3D cellular culture-driven mechanotransduction. Indeed, we found that cell mechanics, dictated by the physical constraints of 3D collagen scaffolds, profoundly affect cellular proliferation in a YAP–mTOR-mediated manner. Functionally, the YAP–mTOR connection is key to mediate cell plasticity in hepatic tumor cell lines. These findings expand the role of YAP–mTOR-driven mechanotransduction to the control hepatic tumor cellular responses under physical constraints in 3D cultures. We suggest a tentative mechanism, which coordinates signaling rewiring with cytoplasmic restructuring during cell growth in 3D microenvironments.
Adam Frtús; Barbora Smolková; Mariia Uzhytchak; Mariia Lunova; Milan Jirsa; Martin Hof; Piotr Jurkiewicz; Vladimir I. Lozinsky; Lucie Wolfová; Yuriy Petrenko; Šárka Kubinová; Alexandr Dejneka; Oleg Lunov. Hepatic Tumor Cell Morphology Plasticity under Physical Constraints in 3D Cultures Driven by YAP–mTOR Axis. Pharmaceuticals 2020, 13, 430 .
AMA StyleAdam Frtús, Barbora Smolková, Mariia Uzhytchak, Mariia Lunova, Milan Jirsa, Martin Hof, Piotr Jurkiewicz, Vladimir I. Lozinsky, Lucie Wolfová, Yuriy Petrenko, Šárka Kubinová, Alexandr Dejneka, Oleg Lunov. Hepatic Tumor Cell Morphology Plasticity under Physical Constraints in 3D Cultures Driven by YAP–mTOR Axis. Pharmaceuticals. 2020; 13 (12):430.
Chicago/Turabian StyleAdam Frtús; Barbora Smolková; Mariia Uzhytchak; Mariia Lunova; Milan Jirsa; Martin Hof; Piotr Jurkiewicz; Vladimir I. Lozinsky; Lucie Wolfová; Yuriy Petrenko; Šárka Kubinová; Alexandr Dejneka; Oleg Lunov. 2020. "Hepatic Tumor Cell Morphology Plasticity under Physical Constraints in 3D Cultures Driven by YAP–mTOR Axis." Pharmaceuticals 13, no. 12: 430.
Macroporous poly(vinyl alcohol) cryogels (PVACGs) are physical gels formed via cryogenic processing of polymer solutions. The properties of PVACGs depend on many factors: the characteristics and concentration of PVA, the absence or presence of foreign solutes, and the freezing-thawing conditions. These factors also affect the macroporous morphology of PVACGs, their total porosity, pore size and size distribution, etc. In this respect, there is the problem with developing a scientifically-grounded classification of the morphological features inherent in various PVACGs. In this study PVA cryogels have been prepared at different temperatures when the initial polymer solutions contained chaotropic or kosmotropic additives. After the completion of gelation, the rigidity and heat endurance of the resultant PVACGs were evaluated, and their macroporous structure was investigated using optical microscopy. The images obtained were treated mathematically, and deep neural networks were used for the classification of these images. Training and test sets were used for their classification. The results of this classification for the specific deep neural network architecture are presented, and the morphometric parameters of the macroporous structure are discussed. It was found that deep neural networks allow us to reliably classify the type of additive or its absence when using a combined dataset.
Ilya I. Kurochkin; Ilya N. Kurochkin; Olga Yu. Kolosova; Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems †: Application of Deep Neural Networks for the Classification of Structural Features Peculiar to Macroporous Poly(vinyl alcohol) Cryogels Prepared without and with the Additives of Chaotropes or Kosmotropes. Molecules 2020, 25, 4480 .
AMA StyleIlya I. Kurochkin, Ilya N. Kurochkin, Olga Yu. Kolosova, Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems †: Application of Deep Neural Networks for the Classification of Structural Features Peculiar to Macroporous Poly(vinyl alcohol) Cryogels Prepared without and with the Additives of Chaotropes or Kosmotropes. Molecules. 2020; 25 (19):4480.
Chicago/Turabian StyleIlya I. Kurochkin; Ilya N. Kurochkin; Olga Yu. Kolosova; Vladimir I. Lozinsky. 2020. "Cryostructuring of Polymeric Systems †: Application of Deep Neural Networks for the Classification of Structural Features Peculiar to Macroporous Poly(vinyl alcohol) Cryogels Prepared without and with the Additives of Chaotropes or Kosmotropes." Molecules 25, no. 19: 4480.
The processes of cryostructuring in polymeric systems, the techniques of the preparation of diverse cryogels and cryostructurates, the physico-chemical mechanisms of their formation, and the applied potential of these advanced polymer materials are all of high scientific and practical interest in many countries. This review article describes and discusses the results of more than 40 years of studies in this field performed by the researchers from the A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences—one of the key centers, where such investigations are carried out. The review includes brief historical information, the description of the main effects and trends characteristic of the cryostructuring processes, the data on the morphological specifics inherent in the polymeric cryogels and cryostructurates, and examples of their implementation for solving certain applied tasks.
Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 55. Retrospective View on the More than 40 Years of Studies Performed in the A.N.Nesmeyanov Institute of Organoelement Compounds with Respect of the Cryostructuring Processes in Polymeric Systems. Gels 2020, 6, 29 .
AMA StyleVladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 55. Retrospective View on the More than 40 Years of Studies Performed in the A.N.Nesmeyanov Institute of Organoelement Compounds with Respect of the Cryostructuring Processes in Polymeric Systems. Gels. 2020; 6 (3):29.
Chicago/Turabian StyleVladimir I. Lozinsky. 2020. "Cryostructuring of Polymeric Systems. 55. Retrospective View on the More than 40 Years of Studies Performed in the A.N.Nesmeyanov Institute of Organoelement Compounds with Respect of the Cryostructuring Processes in Polymeric Systems." Gels 6, no. 3: 29.
This study describes the preparation of nanoparticles derived from bovine serum albumin (BSA) in comparison with the formation of nanoparticles composed of human serum albumin (HSA), when the same preparation procedure was used in both cases. To obtain protein nanoparticles, the method of desolvation with ethanol was employed, followed by the stabilization with urea and cysteine. It was shown that, upon transition from HSA to BSA, the particles with smaller sizes and with a narrower polydispersity were formed. The possibility of the immobilization of the antitumor drug hydroxyurea in such protein nanoparticles by adsorption and inclusion methods has been shown. The drug release profile from the polymer matrix was established.
Yerkeblan Tazhbayev; Olzhas Mukashev; Meiram Burkeyev; Vladimir I. Lozinsky. Synthesis and Comparative Study of Nanoparticles Derived from Bovine and Human Serum Albumins. Polymers 2020, 12, 1301 .
AMA StyleYerkeblan Tazhbayev, Olzhas Mukashev, Meiram Burkeyev, Vladimir I. Lozinsky. Synthesis and Comparative Study of Nanoparticles Derived from Bovine and Human Serum Albumins. Polymers. 2020; 12 (6):1301.
Chicago/Turabian StyleYerkeblan Tazhbayev; Olzhas Mukashev; Meiram Burkeyev; Vladimir I. Lozinsky. 2020. "Synthesis and Comparative Study of Nanoparticles Derived from Bovine and Human Serum Albumins." Polymers 12, no. 6: 1301.
The goal of this study was to reveal how the chemical modification, succinylation in this case, of the wide-pore serum-albumin-based cryogels affects on their osmotic characteristics (swelling extent), biodegradability and ability to be loaded with the bactericide substance – dioxidine, as well as on its release. The cryogels were prepared via the cryogenic processing (freezing – frozen storage – thawing) of aqueous solutions containing bovine serum albumin (50 g/L), denaturant (urea or guanidine hydrochloride, 1.0 mol/L) and reductant (cysteine, 0.01 mol/L). Freezing/frozen storage temperatures were either −15, or −20, or −25 °C. After defrosting, spongy cryogels were obtained that possessed the system of interconnected gross pores, whose shape and dimensions were dependent on the freezing temperature and on the type of denaturant introduced in the feed solution. Subsequent succinylation of the resultant cryogels caused the growth of the swelling degree of the pore walls of these spongy materials, resulted in strengthening of their resistance against of trypsinolysis and gave rise to an increase in their loading capacity with respect to dioxidine. With that, the microbiological tests showed a higher bactericidal activity of the dioxidine-loaded sponges based on the succinylated albumin cryogels as compared to that of the drug-carriers based on the non-modified protein sponges.
Vladimir I. Lozinsky; Anastasiya O. Shchekoltsova; Ekaterina S. Sinitskaya; Olga I. Vernaya; Anastasiya V. Nuzhdina; Irina V. Bakeeva; Mariam G. Ezernitskaya; Alexander M. Semenov; Tatyana I. Shabatina; Mikhail Ya. Melnikov. Influence of succinylation of a wide-pore albumin cryogels on their properties, structure, biodegradability, and release dynamics of dioxidine loaded in such spongy carriers. International Journal of Biological Macromolecules 2020, 160, 583 -592.
AMA StyleVladimir I. Lozinsky, Anastasiya O. Shchekoltsova, Ekaterina S. Sinitskaya, Olga I. Vernaya, Anastasiya V. Nuzhdina, Irina V. Bakeeva, Mariam G. Ezernitskaya, Alexander M. Semenov, Tatyana I. Shabatina, Mikhail Ya. Melnikov. Influence of succinylation of a wide-pore albumin cryogels on their properties, structure, biodegradability, and release dynamics of dioxidine loaded in such spongy carriers. International Journal of Biological Macromolecules. 2020; 160 ():583-592.
Chicago/Turabian StyleVladimir I. Lozinsky; Anastasiya O. Shchekoltsova; Ekaterina S. Sinitskaya; Olga I. Vernaya; Anastasiya V. Nuzhdina; Irina V. Bakeeva; Mariam G. Ezernitskaya; Alexander M. Semenov; Tatyana I. Shabatina; Mikhail Ya. Melnikov. 2020. "Influence of succinylation of a wide-pore albumin cryogels on their properties, structure, biodegradability, and release dynamics of dioxidine loaded in such spongy carriers." International Journal of Biological Macromolecules 160, no. : 583-592.
New hybrid nanosystems containing the antibacterial substances dioxidine or gentamicin sulfate with bioactive metal (Ag, Cu) nanoparticles have been obtained by a cryogenic freeze-drying method and incorporate further the nanocomposites thus obtained into the cryogenically structured biopolymeric matrices based on gelatin, calcium alginate, and chitosan. FTIR, UV-visible, and NMR spectroscopy, TEM and SEM microscopy data show that the resulting systems consist of wide-porous polymer sponges (pore diameters, 10–200 μm) that contain antibacterial drugs and silver (2–30 nm) or copper (1–5 nm) nanoparticles. The investigation showed that these systems ensure a gradual release of dioxidine (from 40 min up to 3 days), depending on the nature of the matrix and its microstructure. The higher activity of hybrid composites based on nanometals and dioxidine or incorporated into cryostructured biopolymer matrices against the bacterial strains of Escherichia coli 52, Staphylococcus aureus 144 is demonstrated as compared to the individual components in the same matrices.
Tatyana I. Shabatina; Olga I. Vernaya; Vladimir P. Shabatin; Michail Y. Melnikov; Alexandr M. Semenov; Vladimir I. Lozinsky. Metal Nanoparticle Containing Nanocomposites of Drug Substances and Their Potential Biomedical Applications. Applied Sciences 2019, 10, 170 .
AMA StyleTatyana I. Shabatina, Olga I. Vernaya, Vladimir P. Shabatin, Michail Y. Melnikov, Alexandr M. Semenov, Vladimir I. Lozinsky. Metal Nanoparticle Containing Nanocomposites of Drug Substances and Their Potential Biomedical Applications. Applied Sciences. 2019; 10 (1):170.
Chicago/Turabian StyleTatyana I. Shabatina; Olga I. Vernaya; Vladimir P. Shabatin; Michail Y. Melnikov; Alexandr M. Semenov; Vladimir I. Lozinsky. 2019. "Metal Nanoparticle Containing Nanocomposites of Drug Substances and Their Potential Biomedical Applications." Applied Sciences 10, no. 1: 170.
In the present work, innovative composite biomaterials possessing bactericidal properties and based on the hexahistidine-tagged organophosphorus hydrolase (His6-OPH) entrapped in the poly(vinyl alcohol) cryogel (PVA-CG)/bacterial cellulose (BC) were developed. His6-OPH possesses lactonase activity, with a number of N-acyl homoserine lactones being the inducers of Gram-negative bacterial resistance. The enzyme can also be combined with various antimicrobial agents (antibiotics and antimicrobial peptides) to improve the efficiency of their action. In this study, such an effect was shown for composite biomaterials when His6-OPH was entrapped in PVA-CG/BC together with β-lactam antibiotic meropenem or antimicrobial peptides temporin A and indolicidin. The residual catalytic activity of immobilized His6-OPH was 60% or more in all the composite samples. In addition, the presence of BC filler in the PVA-CG composite resulted in a considerable increase in the mechanical strength and heat endurance of the polymeric carrier compared to the BC-free cryogel matrix. Such enzyme-containing composites could be interesting in the biomedical field to help overcome the problem of antibiotic resistance of pathogenic microorganisms.
Aysel Aslanli; Nikolay Stepanov; Tatyana Razheva; Elena A. Podorozhko; Ilya Lyagin; Vladimir I. Lozinsky; Elena Efremenko. Enzymatically Functionalized Composite Materials Based on Nanocellulose and Poly(Vinyl Alcohol) Cryogel and Possessing Antimicrobial Activity. Materials 2019, 12, 3619 .
AMA StyleAysel Aslanli, Nikolay Stepanov, Tatyana Razheva, Elena A. Podorozhko, Ilya Lyagin, Vladimir I. Lozinsky, Elena Efremenko. Enzymatically Functionalized Composite Materials Based on Nanocellulose and Poly(Vinyl Alcohol) Cryogel and Possessing Antimicrobial Activity. Materials. 2019; 12 (21):3619.
Chicago/Turabian StyleAysel Aslanli; Nikolay Stepanov; Tatyana Razheva; Elena A. Podorozhko; Ilya Lyagin; Vladimir I. Lozinsky; Elena Efremenko. 2019. "Enzymatically Functionalized Composite Materials Based on Nanocellulose and Poly(Vinyl Alcohol) Cryogel and Possessing Antimicrobial Activity." Materials 12, no. 21: 3619.
Wide-pore cryostructurates were prepared via freezing sodium alginate aqueous solutions with subsequent ice sublimation from the frozen samples, followed by their incubation in the ethanol solutions of calcium chloride or sulfuric acid, rinsing, and final drying. Such sequence of operations resulted in the calcium alginate or alginic acid sponges, respectively. The swelling degree of the walls of macropores in such matrices decreased with increasing polymer concentration in the initial solution. The dependence of the degree of swelling on the cryogenic processing temperature had a bell-like character with a maximum for the samples formed at −20 °C. According to 1H NMR spectroscopy, the content of mobile (non-frozen) water in the frozen water-sodium alginate systems also depended on the initial polymer concentration and freezing temperature. The cryostructurates obtained did not lose their integrity in water, saline, in an acidic medium at pH 2 for at least three weeks. Under alkaline conditions at pH 12 the first signs of dissolution of the Ca-alginate sponge arose only after a week of incubation. Microbiological testing of the model depot form of the antibiotics entrapped in the Ca-alginate cryostructurate demonstrated the efficiency of this system as the antibacterial material.
Natalia D. Zvukova; Tamara P. Klimova; Roman V. Ivanov; Andrei N. Ryabev; Archil V. Tsiskarashvili; Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 52. Properties, Microstructure and an Example of a Potential Biomedical Use of the Wide-Pore Alginate Cryostructurates. Gels 2019, 5, 25 .
AMA StyleNatalia D. Zvukova, Tamara P. Klimova, Roman V. Ivanov, Andrei N. Ryabev, Archil V. Tsiskarashvili, Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 52. Properties, Microstructure and an Example of a Potential Biomedical Use of the Wide-Pore Alginate Cryostructurates. Gels. 2019; 5 (2):25.
Chicago/Turabian StyleNatalia D. Zvukova; Tamara P. Klimova; Roman V. Ivanov; Andrei N. Ryabev; Archil V. Tsiskarashvili; Vladimir I. Lozinsky. 2019. "Cryostructuring of Polymeric Systems. 52. Properties, Microstructure and an Example of a Potential Biomedical Use of the Wide-Pore Alginate Cryostructurates." Gels 5, no. 2: 25.
Composite poly(vinyl alcohol) (PVA) cryogels comprising dispersed porous cellulose-containing fillers (microcrystalline cellulose, wood sawdust) and salting-out electrolytes (Na2SO4, NaF) have been prepared by freezing at –20°C, incubation in the frozen state for 12 h, and defrosting at a rate of 0.03°C/min. The influence of the chemical nature and concentration of the soluble additives and fillers on the rheological behavior of initial suspensions, as well as the morphology of macropores and physicochemical and thermophysical properties of corresponding composite cryogels, has been studied. Viscometric studies have shown that, because of the salting-out action of the electrolytes, the viscosity of PVA solutions decreases due to the compaction of macromolecular coils. However, in the case of filler suspensions, the viscosity increases owing to the enhancement of the adhesion interactions between the discrete and continuous phases, thereby affecting the rigidity and heat endurance of filled cryogels resulting from the freezing–defrosting of such suspensions. The most pronounced increase in the compression elasticity modulus and heat endurance of the composites takes place upon the combined incorporation of a porous filler and a salting-out electrolyte into the cryogel matrix. The microstructure of both unfilled and filled cryogels has been studied by scanning electron microscopy. Substantial changes have been revealed in the macroporous morphology of these objects upon the incorporation of a porous dispersed cellulose-containing filler or a salting-out electrolyte separately and, especially, upon their combined incorporation into the matrix of the PVA cryogel.
E. A. Podorozhko; V. G. Vasil’Ev; N. K. Vasiliev; V. I. Lozinsky. A Study of Cryostructuring of Polymer Systems. 51. The Combined Influence of Porous Cellulose-Containing Dispersed Fillers and Salting-Out Electrolytes on the Physicochemical Properties of Composite Poly(vinyl alcohol) Cryogels. Colloid Journal 2019, 81, 261 -271.
AMA StyleE. A. Podorozhko, V. G. Vasil’Ev, N. K. Vasiliev, V. I. Lozinsky. A Study of Cryostructuring of Polymer Systems. 51. The Combined Influence of Porous Cellulose-Containing Dispersed Fillers and Salting-Out Electrolytes on the Physicochemical Properties of Composite Poly(vinyl alcohol) Cryogels. Colloid Journal. 2019; 81 (3):261-271.
Chicago/Turabian StyleE. A. Podorozhko; V. G. Vasil’Ev; N. K. Vasiliev; V. I. Lozinsky. 2019. "A Study of Cryostructuring of Polymer Systems. 51. The Combined Influence of Porous Cellulose-Containing Dispersed Fillers and Salting-Out Electrolytes on the Physicochemical Properties of Composite Poly(vinyl alcohol) Cryogels." Colloid Journal 81, no. 3: 261-271.
Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in DMSO medium, the URE and GHC additives caused the opposite effects to those observed in water, i.e., the formation of the PVA cryogels (PVACGs) was strengthened rather than inhibited. Our studies of this phenomenon showed that such “kosmotropic-like” effects were more pronounced for the PVACGs that were formed in DMSO in the presence of URE additives, with the effects being concentration-dependent. The additives also caused significant changes in the macroporous morphology of the cryogels; the commonly observed trend was a decrease in the structural regularity of the additive-containing samples compared to the additive-free gel sample. The viscosity measurements revealed consistent changes in the intrinsic viscosity, Huggins constant, and the excess activation heat of the viscosity caused by the additives. The results obtained evidently point to the urea-induced decrease in the solvation ability of DMSO with respect to PVA. As a result, this effect can be the key factor that is responsible for strengthening the structure formation upon the freeze–thaw gelation of this polymer in DMSO additionally containing additives such as urea, which is capable of competing with PVA for the solvent.
Vladimir I. Lozinsky; Olga Yu. Kolosova; Dmitrii A. Michurov; Alexander S. Dubovik; Viktor G. Vasil’Ev; Valerij Ya. Grinberg. Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO. Gels 2018, 4, 81 .
AMA StyleVladimir I. Lozinsky, Olga Yu. Kolosova, Dmitrii A. Michurov, Alexander S. Dubovik, Viktor G. Vasil’Ev, Valerij Ya. Grinberg. Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO. Gels. 2018; 4 (4):81.
Chicago/Turabian StyleVladimir I. Lozinsky; Olga Yu. Kolosova; Dmitrii A. Michurov; Alexander S. Dubovik; Viktor G. Vasil’Ev; Valerij Ya. Grinberg. 2018. "Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO." Gels 4, no. 4: 81.
A variety of cryogenically-structured polymeric materials are of significant scientific and applied interest in various areas. However, in spite of considerable attention to these materials and intensive elaboration of their new examples, as well as the impressive growth in the number of the publications and patents on this topic over the past two decades, a marked variability of the used terminology and definitions is frequently met with in the papers, reviews, theses, patents, conference presentations, advertising materials and so forth. Therefore, the aim of this brief communication is to specify the basic terms and definitions in the particular field of macromolecular science.
Vladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 50.† Cryogels and Cryotropic Gel-Formation: Terms and Definitions. Gels 2018, 4, 77 .
AMA StyleVladimir I. Lozinsky. Cryostructuring of Polymeric Systems. 50.† Cryogels and Cryotropic Gel-Formation: Terms and Definitions. Gels. 2018; 4 (3):77.
Chicago/Turabian StyleVladimir I. Lozinsky. 2018. "Cryostructuring of Polymeric Systems. 50.† Cryogels and Cryotropic Gel-Formation: Terms and Definitions." Gels 4, no. 3: 77.
Poly(vinyl alcohol) (PVA) cryogels (PVACGs) are obtained and studied. The PVACGs are formed by freezing–defrosting of polymer solutions in dimethyl sulfoxide (DMSO) or its mixtures with one of the first members of the series low-molecular-mass aliphatic alcohols (methanol, ethanol, n-propanol, and n-butanol). PVA content in these solutions is 100 g/L, while the concentration of an aliphatic alcohol is varied in a range of 0.44–2.55 mol/L depending on its nature. The polymer solutions are subjected to the cryogenic treatment at temperatures 30, 40, or 50°C lower than the crystallization temperature of DMSO (+18.4°C). The frozen samples are defrosted at a heating rate of 0.03°C/min. It is shown that, in a certain range of lowmolecular-mass alcohol content in an initial system, its cryogenic treatment yields coarse-pored heterophase cryogels that have higher rigidity and heat endurance than those of DMSO–PVA cryogels. It has been shown that polymer cryoconcentration and phase separation play important roles in the formation of a cellular microstructure and an increase in the rigidity and heat endurance of PVACGs obtained in the presence of low-molecular-mass alcohols.
V. I. Lozinsky; I. M. Leonova; R. V. Ivanov; I. V. Bakeeva. A study of cryostructuring of polymer systems. 46. physicochemical properties and microstructure of poly(vinyl alcohol) cryogels formed from polymer solutions in mixtures of dimethyl sulfoxide with low-molecular-mass alcohols. Colloid Journal 2017, 79, 788 -796.
AMA StyleV. I. Lozinsky, I. M. Leonova, R. V. Ivanov, I. V. Bakeeva. A study of cryostructuring of polymer systems. 46. physicochemical properties and microstructure of poly(vinyl alcohol) cryogels formed from polymer solutions in mixtures of dimethyl sulfoxide with low-molecular-mass alcohols. Colloid Journal. 2017; 79 (6):788-796.
Chicago/Turabian StyleV. I. Lozinsky; I. M. Leonova; R. V. Ivanov; I. V. Bakeeva. 2017. "A study of cryostructuring of polymer systems. 46. physicochemical properties and microstructure of poly(vinyl alcohol) cryogels formed from polymer solutions in mixtures of dimethyl sulfoxide with low-molecular-mass alcohols." Colloid Journal 79, no. 6: 788-796.
Composite cryogels simulating the properties of waterproof screens of hydraulic structures, such as protruding dykes and dams, have been obtained by a cryogenic treatment (freezing at –10…–30°C followed by incubation in the frozen state for 12 h and defrosting at a rate of 0.03°C/min) of suspensions of calcium-carbonate-containing (marble or coquina) or cellulose-containing (microcrystalline cellulose or sawdust) particles in aqueous poly(vinyl alcohol) solutions. Viscometric examinations of initial suspensions have shown that adhesion contacts arise between filler particles, as well as discrete and continuous phases, already at the stage of suspension preparation, thereby affecting the properties of resulting cryogels. This is most pronounced when high-porosity sawdust is used as a filler. It has been shown that all the dispersed materials used in the work are “active” fillers for poly(vinyl alcohol) cryogels, these fillers increasing the rigidity of the formed composites. Therewith, porous particles, into which the polymer solution can penetrate, are more efficient. The dependence of the composite rigidity on the temperature of the cryogenic treatment has, as a rule, a bell-shaped pattern with a maximum in the region of –20°C. Being tested for water permeability, the obtained model composite cryogels have exhibited pronounced antifiltration properties (the filtration coefficient is ≤(1–2) × 10–9 cm/s), thus indicating that such materials are promising for solving problems relevant to the protection of fascine hydraulic structures from erosion with snow water.
V. I. Lozinsky; E. A. Podorozhko; Ya. B. Nikitina; L. F. Klabukova; V. G. Vasil’Ev; A. A. Burmistrov; Yu. G. Kondrashov; N. K. Vasiliev. A study of cryostructuring of polymer systems. 45. Effect of porosity of dispersed filler on physicochemical characteristics of composite poly(vinyl alcohol) cryogels. Colloid Journal 2017, 79, 497 -507.
AMA StyleV. I. Lozinsky, E. A. Podorozhko, Ya. B. Nikitina, L. F. Klabukova, V. G. Vasil’Ev, A. A. Burmistrov, Yu. G. Kondrashov, N. K. Vasiliev. A study of cryostructuring of polymer systems. 45. Effect of porosity of dispersed filler on physicochemical characteristics of composite poly(vinyl alcohol) cryogels. Colloid Journal. 2017; 79 (4):497-507.
Chicago/Turabian StyleV. I. Lozinsky; E. A. Podorozhko; Ya. B. Nikitina; L. F. Klabukova; V. G. Vasil’Ev; A. A. Burmistrov; Yu. G. Kondrashov; N. K. Vasiliev. 2017. "A study of cryostructuring of polymer systems. 45. Effect of porosity of dispersed filler on physicochemical characteristics of composite poly(vinyl alcohol) cryogels." Colloid Journal 79, no. 4: 497-507.
The microstructure of complex and composite poly(vinyl alcohol) (PVA) cryogels containing water-soluble chitosan hydrochloride (ChHC) of dispersed particles of water-insoluble chitosan base (Ch), respectively, has been studied by optical microscopy and attenuated total reflection FTIR spectroscopy. The macroporous morphology of cryogels has been studied using preparations in the form of thin (~10 μm) sections and discs 1 mm thick. The introduction of non-gelling additives (NaCl and ChHC) into an initial PVA solution causes significant changes in the size and shapes of macropores in the complex cryogels formed by freezing–defrosting, as compared with the pores in the samples obtained under the same conditions without additives. The reasons for the changes are the process of phase segregation and the influence of low- and high-molecular-weight electrolytes on crystallization of ice, which plays the role of a porogen upon cryotropic gelation of aqueous PVA solutions. As a result of an alkaline treatment of the complex cryogels, which transforms ChHC into Ch, microcoagulation of chitosan yields discrete, almost spherical, particles with sizes of about 1–5 μm. IR spectral studies have shown that concentration gradients of the gelling and nongelling polymers arise along the thickness of the gel discs, with PVA concentration prevailing near the lower surface and ChHC or Ch concentration dominating near the upper surface of the disc.
E. A. Podorozhko; G. R. Ul’Yabaeva; V. E. Tikhonov; A. V. Grachev; L. V. Vladimirov; Yu. A. Antonov; N. R. Kil’Deeva; V. I. Lozinsky. A study of cryostructuring of polymer systems. 43. Characteristics of microstructure of chitosan-containing complex and composite poly(vinyl alcohol) cryogels. Colloid Journal 2017, 79, 94 -105.
AMA StyleE. A. Podorozhko, G. R. Ul’Yabaeva, V. E. Tikhonov, A. V. Grachev, L. V. Vladimirov, Yu. A. Antonov, N. R. Kil’Deeva, V. I. Lozinsky. A study of cryostructuring of polymer systems. 43. Characteristics of microstructure of chitosan-containing complex and composite poly(vinyl alcohol) cryogels. Colloid Journal. 2017; 79 (1):94-105.
Chicago/Turabian StyleE. A. Podorozhko; G. R. Ul’Yabaeva; V. E. Tikhonov; A. V. Grachev; L. V. Vladimirov; Yu. A. Antonov; N. R. Kil’Deeva; V. I. Lozinsky. 2017. "A study of cryostructuring of polymer systems. 43. Characteristics of microstructure of chitosan-containing complex and composite poly(vinyl alcohol) cryogels." Colloid Journal 79, no. 1: 94-105.
E. A. Podorozhko; G. R. Ul’Yabaeva; N. R. Kil’Deeva; V. E. Tikhonov; Yu. A. Antonov; I. L. Zhuravleva; V. I. Lozinsky. A Study of cryostructuring of polymer systems. 41. Complex and composite poly(vinyl alcohol) cryogels containing soluble and insoluble forms of chitosan, respectively. Colloid Journal 2016, 78, 90 -101.
AMA StyleE. A. Podorozhko, G. R. Ul’Yabaeva, N. R. Kil’Deeva, V. E. Tikhonov, Yu. A. Antonov, I. L. Zhuravleva, V. I. Lozinsky. A Study of cryostructuring of polymer systems. 41. Complex and composite poly(vinyl alcohol) cryogels containing soluble and insoluble forms of chitosan, respectively. Colloid Journal. 2016; 78 (1):90-101.
Chicago/Turabian StyleE. A. Podorozhko; G. R. Ul’Yabaeva; N. R. Kil’Deeva; V. E. Tikhonov; Yu. A. Antonov; I. L. Zhuravleva; V. I. Lozinsky. 2016. "A Study of cryostructuring of polymer systems. 41. Complex and composite poly(vinyl alcohol) cryogels containing soluble and insoluble forms of chitosan, respectively." Colloid Journal 78, no. 1: 90-101.
V. I. Lozinsky; O. E. Zaborina; T. P. Klimova; T. A. Babushkina; A. S. Kovaleva; Ekaterina Boltukhina; V. P. Chernyshev; T. V. Burova; N. V. Grinberg; A. R. Khokhlov. Copolymers containing functional groups intrinsic to the active centers of serine hydrolases: Synthesis and evaluation of catalytic capability. Polymer Science, Series B 2016, 58, 27 -37.
AMA StyleV. I. Lozinsky, O. E. Zaborina, T. P. Klimova, T. A. Babushkina, A. S. Kovaleva, Ekaterina Boltukhina, V. P. Chernyshev, T. V. Burova, N. V. Grinberg, A. R. Khokhlov. Copolymers containing functional groups intrinsic to the active centers of serine hydrolases: Synthesis and evaluation of catalytic capability. Polymer Science, Series B. 2016; 58 (1):27-37.
Chicago/Turabian StyleV. I. Lozinsky; O. E. Zaborina; T. P. Klimova; T. A. Babushkina; A. S. Kovaleva; Ekaterina Boltukhina; V. P. Chernyshev; T. V. Burova; N. V. Grinberg; A. R. Khokhlov. 2016. "Copolymers containing functional groups intrinsic to the active centers of serine hydrolases: Synthesis and evaluation of catalytic capability." Polymer Science, Series B 58, no. 1: 27-37.
Composite macroporous poly(vinyl alcohol) (PVA) cryogels have been prepared by cryogenic treatment (freezing at −20°C for 12 h followed by defrosting at a rate of 0.03°C/min) of dispersions of chitosan particles swollen in an aqueous 120 g/L PVA solution. The elasticity moduli and fusion temperatures have been determined for corresponding samples, and their microstructure has been investigated by optical microscopic examination of their thin sections. The rigidity and heat endurance of the PVA-chitosan composite cryogels have been shown to increase with filler concentration. In addition, the rheological properties of initial dispersions have been studied and the appearance of adhesion contacts between discrete and continuous phases has been revealed already at the stage of dispersion preparation. The optical microscopic investigations of the morphological features of the initial dispersions and the microstructure of the composites have established a relatively uniform distribution of filler particles in the bulk of composite cryogels. It has been shown that chitosan particles incorporated into the matrix of the macroporous PVA cryogel are capable of sorbing heavy metal ions—in particular, bivalent copper ions—from aqueous solutions.
E. A. Podorozhko; I. A. Lunev; A. N. Ryabev; N. R. Kil’Deeva; Vladimir I Lozinsky. A study of cryostructuring of a polymer system. 39. Poly(vinyl alcohol) composite cryogels filled with chitosan microparticles. Colloid Journal 2015, 77, 186 -195.
AMA StyleE. A. Podorozhko, I. A. Lunev, A. N. Ryabev, N. R. Kil’Deeva, Vladimir I Lozinsky. A study of cryostructuring of a polymer system. 39. Poly(vinyl alcohol) composite cryogels filled with chitosan microparticles. Colloid Journal. 2015; 77 (2):186-195.
Chicago/Turabian StyleE. A. Podorozhko; I. A. Lunev; A. N. Ryabev; N. R. Kil’Deeva; Vladimir I Lozinsky. 2015. "A study of cryostructuring of a polymer system. 39. Poly(vinyl alcohol) composite cryogels filled with chitosan microparticles." Colloid Journal 77, no. 2: 186-195.
Composite macroporous poly(vinyl alcohol) (PVA) cryogels have been prepared by cryogenic treatment (freezing at −20°C for 12 h followed by thawing at a rate of 0.03°C/min) of mixtures of an aqueous PVA solution and poly(butadiene-co-styrene) latex. The values of the elasticity modulus and fusion temperature have been determined for the obtained samples, and their microstructures have been studied by optical microscopy of thin sections. The rigidity and heat endurance of the filled cryogels have been shown to markedly increase with the fraction of the latex in the initial liquid disperse system. Moreover, it has been found that, beginning from some critical concentration of the latex in a mixture with the initial PVA solution, cryostructuring leads to the formation of two interpenetrating phases—a continuous phase of the hydrophilic PVA cryogel and a network of the hydrophobic phase that results from cryocoagulation of non-frost-resistant poly(butadiene-co-styrene) latex. The morphological features of this phase have been studied, and the sizes of macropores and the thicknesses of their walls have been determined with the help of scanning electron microscopy.
E. A. Podorozhko; E. A. D’Yakonova; V. I. Lozinsky. A study of cryostructuring of polymer systems. 37. Composite cryogels formed from dispersions of poly(butadiene-co-styrene) latex in aqueous poly(vinyl alcohol) solution. Colloid Journal 2015, 77, 46 -57.
AMA StyleE. A. Podorozhko, E. A. D’Yakonova, V. I. Lozinsky. A study of cryostructuring of polymer systems. 37. Composite cryogels formed from dispersions of poly(butadiene-co-styrene) latex in aqueous poly(vinyl alcohol) solution. Colloid Journal. 2015; 77 (1):46-57.
Chicago/Turabian StyleE. A. Podorozhko; E. A. D’Yakonova; V. I. Lozinsky. 2015. "A study of cryostructuring of polymer systems. 37. Composite cryogels formed from dispersions of poly(butadiene-co-styrene) latex in aqueous poly(vinyl alcohol) solution." Colloid Journal 77, no. 1: 46-57.