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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Zhila N., Kiselev E., Shishatskaya E.
Заглавие : A study of synthesis and properties of poly-3-hydroxybutyrate/diethylene glycol copolymers
Место публикации : Biotechnol. Prog.: John Wiley and Sons Inc., 2016. - Vol. 32, Is. 4. - С. 1017-1028. - ISSN 87567938 (ISSN) , DOI 10.1002/btpr.2267
Ключевые слова (''Своб.индексиров.''): biocompatibility--biosynthesis--molecular weight--physicochemical and mechanical properties--poly(3-hydroxybutyrate)/diethylene glycol copolymers--biochemistry--biocompatibility--biosynthesis--cell culture--cell membranes--cells--cytology--fatty acids--glycols--molecular weight--american institute of chemical engineers--biological properties--chemical compositions--cytoplasmic membrane--degree of saturations--physico-chemical and mechanical properties--physiological effects--poly-3-hydroxybutyrate--biomechanics
Аннотация: This study investigates synthesis of poly(3-hydroxybutyrate)/diethylene glycol copolymers (P3HB/DEG) by Cupriavidus eutrophus B-10646 cells as related to DEG concentration in the medium and the time when it is added to the culture of cells synthesizing P3HB. The study determines the limits of physiological effect of DEG on C. eutrophus cells, showing that at DEG concentrations above 30 g/L, it inhibits cell growth, decreasing cell concentration and total P3HB/DEG yield and inducing an increase in the degree of saturation of fatty acids in lipids of cell cytoplasmic membrane. A series of copolymers containing different molar fractions of DEG (between 0.13 and 3.0 mol%) have been synthesized and their physicochemical, physical/mechanical, and biological properties have been investigated as related to the chemical composition and proportions of DEG monomers of the polymers. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1017–1028, 2016. © 2016 American Institute of Chemical Engineers
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E.I., Nikolaeva E.D., Goreva A.V., Brigham C.J., Volova T.G., Sinskey A.J.
Заглавие : An in vivo study of pha matrices of different chemical composition: Tissue reaction and biodegradation
Место публикации : Cellular Transplantation and Tissue Engineering. - 2012. - Vol. 7, Is. 1. - С. 73-80. - ISSN 1815445X (ISSN)
Ключевые слова (''Своб.индексиров.''): degradable polymer matrices--degradation--phas--polyhydroxyalkanoates--subcutaneous implantation--tissue reaction
Аннотация: The study addresses consequences of subcutaneous implantation of film matrices prepared from different PHAs to laboratory animals. No negative effects of subcutaneous implantation of PHA matrices on physiological and biochemical characteristics of the animals were determined. Independently of the matrices composition and duration of the contact with the internal environment of the organism we did not observe any deviations in the behavior of animals, their growth and development, as well as blood functions. Response of the tissues to PHA matrices was comparable with the response to polylactide, but substantially less expressed at the earlier time periods after implantation. Tissues response to implantation of PHA of all types is characterized by short-term (up to 2 weeks) post-traumatic inflammation with formation of fibrous capsules by 30th-60th days with the thickness less than 100 microns, which get thinner down to 40-60 microns by 180th day as the result of involution. No differences in response of tissues and the whole organism were observed for the matrices produced from the homopolymer of 3-hydroxybutyric acid (P3HB), copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids (P3HB/4HB), 3-hydroxybutyric acid and 3-hydroxyvalerianic acids (P3HB/3HV), 3-hydroxybutyric and 3-hydroxyhexanoate acids (P3HB/3HH). Macrophages and foreign-body giant cells actively participate in the response of the tissues to PHAs. In the studied conditions matrices from the copolymers containing 3-hydroxyhexanoate and 4 hydroxybutyrate were determined as more actively degraded PHA. The next less degraded matrices were matrices from the copolymer of P3HB/3HV and the most resistant were P3HB matrices. The slower degradation of PHA matrices was accompanied by delayed development of giantcells response. The studied PHA matrices can be placed in the following range by their degradation: P3HB/3HH - P3HB/4HB - P3HB/HV - P3HB.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila N. O., Kalacheva G. S., Fokht V. V., Bubnova S. S., Volova T. G.
Заглавие : Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by cupriavidus necator B-10646 from mixtures of oleic acid and 3-hydroxyvalerate precursors
Место публикации : J. Sib. Fed. Univ. - Biol.: Siberian Federal University, 2020. - Vol. 13, Is. 3. - С. 331-341. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0320
Аннотация: Polyhydroxyalkanoates have attracted much attention as biodegradable alternative to petroleum-based synthetic plastics. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer is one of the best characterized PHA copolymers because of its high commercial potential. However, commercial use of PHAs has been limited by their high price. One approach to reducing the cost of PHA production is to use inexpensive carbon sources (fatty acids, plant oils, etc.). The aim of this work was to study synthesis of P(3HB-co-3HV) by the Cupriavidus necator B-10646 bacterium grown on oleic acid and different biochemical precursors of 3HV. Bacterial cells were grown for 72 h at 30°C and 200 rpm on an incubator shaker. Salts of propionic or valeric acids were used as precursors of 3HV. The content and the composition of the polymer were determined by gas chromatography of fatty acid methyl esters. Lipids and polymer were extracted from biomass using the method of Folch. The addition of potassium propionate and valerate did not inhibit bacterial growth and polymer synthesis, the cell concentration and polymer content reaching 9.3-9.5 g/L and 80-83%, respectively. The addition of potassium valerate or propionate led to the synthesis of (P(3HB-co-3HV)) copolymer containing 21.2 and 14.3 mol% of 3HV, respectively. The number average molecular weight (Mn) of the polymer synthesized by the bacterium on oleic acid alone was 220 kDa; the polydispersity of the polymer was 3.5. The polymer synthesized in the presence of potassium valerate and propionate was characterized by a lower Mn (156-178 kDa) and a higher polydispersity of the polymer (4.4-4.9). The main fatty acids (FA) of intracellular lipids were oleic (33.26% of the total FA) and palmitic acid (27.48% of the total FA). The addition of potassium propionate or valerate did not cause any significant changes in the composition of the FA of intracellular lipids of the strain studied. This study demonstrates the ability of C. necator B-10646 to synthesize P(3HB-co-3HV) from mixtures of oleic acid and 3HV precursors. The data obtained can be used to develop and implement an economically feasible process of the P(3HB-co-3HV) production. © Siberian Federal University. All rights reserved.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Goreva A.V., Shishatskaya E.I., Volova T.G., Sinskey A.J.
Заглавие : Characterization of polymeric microparticles based on resorbable polyesters of oxyalkanoic acids as a platform for deposition and delivery of drugs
Место публикации : Polym. Sci. Ser. A: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2012. - Vol. 54, Is. 2. - С. 94-105. - 12. - ISSN 0965-545X, DOI 10.1134/S0965545X12020022
Примечания : Cited References: 33. - This work was supported by the program for Support of Leading Scientific Schools of the Russian Federation (project no. 11.G34.31.0013.2010, Biotechnology of New Biomaterials) and the program of integrated studies of the Presidium of the Siberian Branch, Russian Academy of Sciences (project no. 93).
Предметные рубрики: IN-VITRO RELEASE
POLYHYDROXYBUTYRATE MICROSPHERES
BLENDS
RIFAMPICIN
BIOCOMPATIBILITY
DEGRADATION
FORMULATION
COMPOSITE
CARRIERS
MODEL
Аннотация: The effect of the preparation technique (chemical composition of a polymer, type and method of emulsion mixing, and molecular mass of a drug) on the yield, structure, and size of microparticles obtained from resorbable polyesters of microbiological origin, polyhydroxyalkanoates, is studied. It is found that the concentration of the polymer solution and the method of emulsion mixing are the most significant factors affecting the diameter of microparticles based on polyhydroxyalkanoates; the surface structure of particles depends to a higher extent on the chemical composition of the polymer. The family of microparticles from 100-200 nm to 50-70 mu m in diameter is synthesized. It is shown that the rate of drug release from microparticles in vitro into the medium is higher in the case of 3-hydroxybutyrate copolymers with 3-hydroxyvalerate than in the case of the homopolymer of 3-hydroxybutyrate. This parameter increases with the content of 3-hydroxyvalerate units in the copolymer and the porosity and mass fraction of the drug in particles with a decrease in their sizes. For in vitro systems containing a phosphate buffer, variation in the preparation parameters makes it possible to obtain microparticles with various characteristics suitable for deposition of drugs. For microparticles obtained from polyhydroxyalkanoates and having different diameters, the mathematical description of the kinetics of drug release from the polymer matrix is provided.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nikolaeva E.D., Shishatskaya E.I., Mochalov K.E., Volova T.G., Sinsky A.J.
Заглавие : Comparative investigation of polyhydroxyalkanoate scaffolds with various chemical compositions
Место публикации : Cellular Transplantation and Tissue Engineering. - 2011. - Vol. 6, Is. 4. - С. 54-63. - ISSN 1815445X (ISSN)
Ключевые слова (''Своб.индексиров.''): biopolymers--scaffolds--tissue engineering
Аннотация: The authors have constructed and characterized a series of membranes based on resorbable polyhydroxyalkanoates of different compositions. Five PHA types have been studied: a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids, 3-hydroxybutyric and 3-hydroxyvaleric acids, 3-hydroxybutyric and 3-hydroxyhexanoic acids. Scanning electron microscopy and atomicforce microscopy were used to examine the microstructure of membrane surfaces, showing that membranes based on the copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate had the roughest surface, while membranes based on the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate had the smoothest surface. The contact angle for water in air was smaller and hydrophilic properties better in the copolymer membranes than in the membranes based on the high-crystallinity homopolymer of 3-hydroxybutyric acid. The culture of mouse fibroblast cell line NIH 3,3 was used to test PHAbased membranes; results of fluorescent probes of DNA DAPI and the MTT assay show that membranes based on studied PHAs are not cytotoxic on direct contact with cells and are highly biocompatible; their adhesive properties and ability to maintain fibroblast proliferation are similar to those of polystyrene and better than those of polylactic acid membranes.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E.I., Volova T.G., Gordeev S.A., Puzyr A.P.
Заглавие : Degradation of P(3HB) and P(3HB-co-3HV) in biological media
Место публикации : Journal of Biomaterials Science, Polymer Edition. - 2005. - Vol. 16, Is. 5. - С. 643-657. - ISSN 09205063 (ISSN) , DOI 10.1163/1568562053783678
Ключевые слова (''Своб.индексиров.''): degradation rate--fiber properties--morphology--poly(hydroxybutyrate-co-hydroxyvalerate) (p(3hb-co-3hv))--polyhydroxyalkanoates(phas)--polyhydroxybutyrate (p(3hb))--copolymers--degradation--differential scanning calorimetry--enzymes--morphology--scanning electron microscopy--tensile strength--tissue--transmission electron microscopy--degradation rate--fiber properties--polyhydroxyalkanoates (phas)--polyhydroxybutyrate (p(3hb))--biopolymers--buffer--copolymer--poly(3 hydroxybutyric acid)--polyhydroxybutyrate hydroxyvalerate copolymer--unclassified drug--animal experiment--animal model--animal tissue--article--biodegradation--controlled study--crystal structure--fiber--giant cell--in vitro study--in vivo study--macrophage--morphology--nonhuman--ph--priority journal--rat--structure analysis--tensile strength--tissue water--weight reduction--animals--biodegradation, environmental--buffers--humans--hydrogen-ion concentration--hydroxybutyrates--macrophages--microscopy, electron, scanning--microscopy, electron, transmission--muscle, skeletal--polyesters--rats--rats, wistar
Аннотация: The biodegradability of oriented fibers made of polyhydroxybutyrate (P(3HB)) and its co-polymer with ?-hydroxyvalerate (P(3HB-co-3HV)) was investigated in buffer solutions and in biological media in vitro and in vivo. The fibers of both polymer types demonstrated resistance to hydrolytic degradation in buffer solutions at 38В°C and pH from 4.5 to 7.0 (for up to 180 days). It has been found that the biodegradation of the fibers in vitro in blood and serum and in vivo is accompanied by weight losses and minor changes in the microstructure with no significant losses in the tensile strength over a long time (up to 180 days). The biodegradation rate of the less crystalline co-polymer P(3HB-co-3HV) fibers was 1.4-2.0-times higher than that of the homopolymer P(3HB). It has also been shown that the degradation of the fibers in vivo is influenced both by tissue fluid enzymes and cells (macrophages and foreign-body giant cells). The fibers were eroded on the surface only with no gross defects and no dramatic effects on their mechanical performance. В© VSP 2005.
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7.

Вид документа :
Шифр издания :
Автор(ы) : Volova T. G., Goncharov D. B., Nikolaeva E. D., Shishatskaya E. I.
Заглавие : Electrospinning of degradable phas: Process, properties, applications
Место публикации :: Nova Science Publishers, Inc., 2017. - С. 1-56
Ключевые слова (''Своб.индексиров.''): biological and physical/mechanical properties--cell proliferation--electrospinning--nonwoven membranes--pha--scaffolds--skin regeneration--ultrafine fibers--wound dressings
Аннотация: An integrated study has been performed to investigate the process of formation of ultrafine fibers and nonwoven membranes by electrospinning from natural degradable polymers-polyhydroxyalkanoates (PHAs); physical, mechanical, and biological properties of the products have been studied. Then, electrospinning was used to prepare ultrafine fibers from PHAs with different compositions: P(3HB) and its copolymers P(3HB-co-4HB), P(3HB-co-3HV), and P(3HB-co-3HHx). The main process parameters, that influence UF-fiber diameter and properties of fibrous non-woven membranes) (polymer concentration, solution feeding rate, working distance, and applied voltage), were investigated and their effects evaluated. This study was the first to compare biological and physical/mechanical parameters of PHAs with different chemical compositions as dependent upon the fractions of monomers, constituting the polymers and fiber orientation. Electrospun polymer membranes, prepared from the [P(3HB-co-4HB)], were tested as wound dressings. The developed nonwoven membranes can be used as the equivalent of collagen skine dressings in the treatment of burns of degree II. Experiments on laboratory animals with model skin defects showed, that the membranes fitted the wound shape good, protected the wound from external influences, and facilitated wound healing, promoting fast repair. The successful experiments on laboratory animals were followed by pilot clinical trials of nanomembranes, comprised of PHA membranes as wound dressings in the treatment of septic wounds. During the regeneration phase, PHA membranes served as a scaffold for the new tissue on the skin and filled out soft tissue defects. The formation of the uniform and sufficiently vascularized tissue is a prerequisite for quicker wound healing and can serve as a basis for the subsequent skin grafting and spontaneous re-epithelialization of superficial wounds. The wound dressing, tested in this clinical trial, performs important physiological functions of natural skin, provides a barrier against secondary infection, reduces fluid loss, and, at the same time, does not keep the air out. © 2017 Nova Science Publishers, Inc.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T..., Goncharov D..., Sukovatyi A..., Shabanov A..., Nikolaeva E..., Shishatskaya E...
Заглавие : Electrospinning of polyhydroxyalkanoate fibrous scaffolds: effects on electrospinning parameters on structure and properties
Колич.характеристики :24 с
Коллективы : Project 'Biotechnologies of novel biomaterials: innovative biopolymers and devices for biomedicine' [1, 11.G34.31.0013]; Government of the Russian Federation [220]; RF President for supporting young Doctors of Sciences [MD-3112.2012.4]
Место публикации : J. Biomater. Sci.-Polym. Ed.: TAYLOR & FRANCIS LTD, 2014. - Vol. 25, Is. 4. - С. 370-393. - ISSN 0920-5063, DOI 10.1080/09205063.2013.862400
Примечания : Cited References: 52. - This study was financially supported by Project 'Biotechnologies of novel biomaterials: innovative biopolymers and devices for biomedicine' (Agreement No. 1 of 15.02.2013 to Agreement No. 11.G34.31.0013) in accordance with Resolution No. 220 of the Government of the Russian Federation of April 9, 2010, 'On measures designed to attract leading scientists to the Russian institutions of higher learning' and Grant of the RF President for supporting young Doctors of Sciences No. MD-3112.2012.4.
Предметные рубрики: TISSUE ENGINEERING APPLICATIONS
FIBER MATS
POLY 3-HYDROXYBUTYRATE
POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE)
BIOCOMPATIBILITY
PROLIFERATION
FABRICATION
NANOFIBERS
COPOLYMERS
MEMBRANES
Ключевые слова (''Своб.индексиров.''): electrospinning--polyhydroxyalkanoates--ultrafine fibers--physical-mechanical properties--fibroblast cells
Аннотация: In this study, electrospinning was used to prepare ultrafine fibers from PHAs with different chemical compositions: P(3HB) and copolymers: P(3HB-co-4HB), P(3HB-co-3HV), and P(3HB-co-3HHx). The main process parameters that influence ultrafine fiber diameter and properties (polymer concentration, solution feeding rate, working distance, and applied voltage) have been investigated and their effects evaluated. The study revealed electrospinning parameters for the production of high-quality ultrafine fibers and determined which parameters should be varied to tailor the properties of the products. This study is the first to compare biological and physical-mechanical parameters of PHAs with different chemical compositions as dependent upon the fractions of monomers constituting the polymers and ultrafine fiber orientation. Mechanical strength of aligned ultrafine fibers prepared from different PHAs is higher than that of randomly oriented ones; no significant effect of ultrafine fiber orientation on surface properties has been found. None of the fibrous scaffolds produced by electrospinning from PHAs had any adverse effects on attachment, growth, and viability of NIH 3T3 mouse fibroblast cells, and all of them were found to be suitable for tissue engineering applications.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Shishatskaya E.I., Nikolaeva E.D., Sinskey A.J.
Заглавие : In vivo study of 2D PHA matrices of different chemical compositions: tissue reactions and biodegradations
Колич.характеристики :9 с
Коллективы : Government of the Russian Federation
Место публикации : Mater. Sci. Technol.: MANEY PUBLISHING, 2014. - Vol. 30, Is. 5. - С. 549-557. - ISSN 0267-0836, DOI 10.1179/1743284713Y.0000000470. - ISSN 1743-2847
Примечания : Cited References: 31. - The study was supported by the project initiated by the Government of the Russian Federation (decree no. 220 of 09.04.2010) for governmental support of scientific research conducted under the guidance of leading scientists at Russian institutions of higher learning (agreement no. 11.G34.31.0013) and the Program of Integrated Research of the Presidium of SB RAS (project no. 96).
Предметные рубрики: BIOMEDICAL INVESTIGATIONS
POLYHYDROXYALKANOATES
VITRO
BIOCOMPATIBILITY
DEGRADATION
SCAFFOLDS
CONDUITS
POLYMERS
Ключевые слова (''Своб.индексиров.''): pha--polyhydroxyalkanoates--biocompatibility--implantation--tissue response--biodegradation
Аннотация: Matrices based on resorbable polyhydroxyalkanoates (PHAs) of five types {a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids [P(3HB/4HB)], 3-hydroxybutyric and 3-hydroxyvaleric acids [P(3HB/3HV)], 3-hydroxybutyric and 3-hydroxyhexanoic acids [P(3HB/3HHx)]} have been constructed and characterised. No significant differences have been found in tissue response to implantation of these PHAs. Non-coarse fibrous capsules that formed around PHA matrices reached their maximum thickness (60-90 mm) 90 days after implantation; by day 180, the average thickness of the capsules had decreased by 1.5- 2.3 times. The number of foreign body giant cells, resorbing PHAs, remained high. In vivo biodegradation behaviour of polymer matrices is related to the chemical composition of the PHA. Matrices prepared from copolymers P(3HB/4HB) and P(3HB/3HHx) exhibited the fastest degradation rates. P3HB/3HV matrices were degraded more slowly, and P3HB matrices were the most durable. In the PHA matrices that were degraded more slowly, giant cell reaction developed later.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Shishatskaya E.I., Nikolaeva E.D., Sinskey A.J.
Заглавие : In vivo study of 2D PHA matrices of different chemical compositions: Tissue reactions and biodegradations
Место публикации : Mater. Sci. Technol. - 2014. - Vol. 30, Is. 5. - С. 549-557. - ISSN 17432847 (ISSN) , DOI 10.1179/1743284713Y.0000000470
Ключевые слова (''Своб.индексиров.''): biocompatibility--biodegradation--implantation--pha--polyhydroxyalkanoates--tissue response--biocompatibility--biodegradable polymers--copolymers--degradation--ion implantation--microbiology--tissue--chemical compositions--foreign body giant cells--hydroxybutyric acids--maximum thickness--pha--polyhydroxyalkanoates--polymer matrices--tissue response--biodegradation
Аннотация: Matrices based on resorbable polyhydroxyalkanoates (PHAs) of five types {a homopolymer of 3- hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids [P(3HB/4HB)], 3-hydroxybutyric and 3-hydroxyvaleric acids [P(3HB/3HV)], 3-hydroxybutyric and 3-hydroxyhexanoic acids [P(3HB/3HHx)]} have been constructed and characterised. No significant differences have been found in tissue response to implantation of these PHAs. Non-coarse fibrous capsules that formed around PHA matrices reached their maximum thickness (60-90 ?m) 90 days after implantation; by day 180, the average thickness of the capsules had decreased by 1·5-2·3 times. The number of foreign body giant cells, resorbing PHAs, remained high. In vivo biodegradation behaviour of polymer matrices is related to the chemical composition of the PHA. Matrices prepared from copolymers P(3HB/4HB) and P(3HB/3HHx) exhibited the fastest degradation rates. P3HB/3HV matrices were degraded more slowly, and P3HB matrices were the most durable. In the PHA matrices that were degraded more slowly, giant cell reaction developed later. © 2014 Institute of Materials, Minerals and Mining.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Golubev, Alexey, I, Nemtsev, Ivan, V, Lukyanenko, Anna, V, Dudaev, Alexey E., Shishatskaya, Ekaterina, I
Заглавие : Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition
Колич.характеристики :24 с
Коллективы : Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations [19-43-240012]; Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 2073-4360(eISSN), DOI 10.3390/polym13101553
Примечания : Cited References:87. - This work was supported by the Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations under Grant number 19-43-240012 (laser treatment and films properties) and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (polymer synthesis).
Предметные рубрики: CHEMOMECHANICAL PROPERTIES
PHYSICOCHEMICAL PROPERTIES
SURFACE
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92 degrees and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80-56 degrees and surface energy and roughness increased to 41-57 mN/m and 172-290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76-80 degrees) and reduced roughness parameters (to 40-45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67-76 degrees), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Golubev A. I., Nemtsev I. V., Lukyanenko A. V., Dudaev A. E., Shishatskaya E. I.
Заглавие : Laser processing of polymer films fabricated from phas differing in their monomer composition
Место публикации : Polym.: MDPI AG, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 20734360 (ISSN), DOI 10.3390/polym13101553
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92? and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80–56? and surface energy and roughness increased to 41–57 mN/m and 172–290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76–80? ) and reduced roughness parameters (to 40–45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67–76? ), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Prudnikova, Svetlana V., Vinogradova, Olga N., Syrvacheva, Darya A., Shishatskaya, Ekaterina I.
Заглавие : Microbial Degradation of Polyhydroxyalkanoates with Different Chemical Compositions and Their Biodegradability
Колич.характеристики :15 с
Коллективы : Russian Science Foundation [14-26-00039]
Место публикации : Microb. Ecol.: SPRINGER, 2017. - Vol. 73, Is. 2. - С. 353-367. - ISSN 0095-3628, DOI 10.1007/s00248-016-0852-3. - ISSN 1432-184X(eISSN)
Примечания : Cited References:65. - This study was supported by the Russian Science Foundation (Grant No. 14-26-00039).
Предметные рубрики: TROPICAL COASTAL WATERS
PHA-DEGRADING BACTERIA
ALCALIGENES-EUTROPHUS
Ключевые слова (''Своб.индексиров.''): degradable polyhydroxyalkanoates--pha--soil--pha-degrading--microorganisms
Аннотация: The study addresses degradation of polyhydroxyalkanoates (PHA) with different chemical compositions-the polymer of 3-hydroxybutyric acid [P(3HB)] and copolymers of P(3HB) with 3-hydroxyvalerate [P(3HB/3HV)], 4-hydroxybutyrate [P(3HB/4HB)], and 3-hydroxyhexanoate [P(3HB/3HHx)] (10-12 mol%)-in the agro-transformed field soil of the temperate zone. Based on their degradation rates at 21 and 28 A degrees C, polymers can be ranked as follows: P(3HB/4HB) P(3HB/3HHx) P(3HB/3HV) P(3HB). The microbial community on the surface of the polymers differs from the microbial community of the soil with PHA specimens in the composition and percentages of species. Thirty-five isolates of bacteria of 16 genera were identified as PHA degraders by the clear zone technique, and each of the PHA had both specific and common degraders. P(3HB) was degraded by bacteria of the genera Mitsuaria, Chitinophaga, and Acidovorax, which were not among the degraders of the three other PHA types. Roseateles depolymerans, Streptomyces gardneri, and Cupriavidus sp. were specific degraders of P(3HB/4HB). Roseomonas massiliae and Delftia acidovorans degraded P(3HB/3HV), and Pseudoxanthomonas sp., Pseudomonas fluorescens, Ensifer adhaerens, and Bacillus pumilus were specific P(3HB/3HHx) degraders. All four PHA types were degraded by Streptomyces.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Murueva A.V., Shishatskaya E.I., Kuzmina A.M., Volova T.G., Sinskey A.J.
Заглавие : Microparticles prepared from biodegradable polyhydroxyalkanoates as matrix for encapsulation of cytostatic drug
Место публикации : Journal of Materials Science: Materials in Medicine. - 2013. - Vol. 24, Is. 8. - С. 1905-1915. - ISSN 09574530 (ISSN) , DOI 10.1007/s10856-013-4941-2
Ключевые слова (''Своб.индексиров.''): 3-hydroxybutyric acid--average diameter--cell attachments--chemical compositions--mass concentration--mouse-fibroblasts--polyhydroxyalkanoates--solvent evaporation techniques--biocompatibility--cell culture--cells--loading--3 hydroxybutyric acid--3 hydroxyhexanoic acid--4 hydroxybutyric acid--4',6 diamidino 2 phenylindole--dna--doxorubicin--nanoparticle--polyhydroxyalkanoic acid--polymer--polystyrene--solvent--unclassified drug--animal cell--article--biocompatibility--biodegradability--cell adhesion--cell proliferation--cell strain 3t3--cell viability--chemical composition--chemical structure--controlled study--cytotoxicity--drug efficacy--drug release--electrophoretic mobility--encapsulation--evaporation--fibroblast--in vitro study--nonhuman--particle size--priority journal--stain--study--surface charge--zeta potential
Аннотация: Microparticles made from degradable polyhydroxyalkanoates of different chemical compositions a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids (P3HB/4HB), 3-hydroxybutyric and 3-hydroxyvaleric acids (P3HB/3HV), 3-hydroxybutyric and 3-hydroxyhexanoic acids (P3HB/3HHx) were prepared using the solvent evaporation technique, from double emulsions. The study addresses the influence of the chemical compositions on the size and ?-potential of microparticles. P3HB microparticles loaded with doxorubicin have been prepared and investigated. Their average diameter and ?-potential have been found to be dependent upon the level of loading (1, 5, and 10 % of the polymer mass). Investigation of the in vitro drug release behavior showed that the total drug released from the microparticle into the medium increased with mass concentration of the drug. In this study mouse fibroblast NIH 3T3 cells were cultivated on PHA microparticles, and results of using fluorescent DAPI DNA stain, and MTT assay showed that microparticles prepared from PHAs of different chemical compositions did not exhibit cytotoxicity to cells cultured on them and proved to be highly biocompatible. Cell attachment and proliferation on PHA microparticles were similar to those on polystyrene. The cytostatic drug encapsulated in P3HB/3HV microparticles has been proven to be effective against HeLa tumor cells. В© 2013 Springer Science+Business Media New York.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Vinogradova O. N., Zhila N. O., Kiselev E. G., Peterson I. V., Vasil’ev A. D., Sukovatyi A. G., Shishatskaya E. I.
Заглавие : Physicochemical properties of multicomponent polyhydroxyalkanoates: Novel aspects
Место публикации : Polym. Sci. Ser. A: Maik Nauka-Interperiodica Publishing, 2017. - Vol. 59, Is. 1. - С. 98-106. - ISSN 0965545X (ISSN) , DOI 10.1134/S0965545X17010163
Ключевые слова (''Своб.индексиров.''): glycols--medical problems--melting--molecular mass--monomers--polymers--chemical compositions--degree of crystallinity--degrees of crystallinity--multi-component polyhydroxyalkanoates--physicochemical property--polyhydroxyalkanoates--temperature intervals--thermal degradation temperatures--organic polymers
Аннотация: The physicochemical properties such as the degree of crystallinity and temperature and molecularmass characteristics of a number of polyhydroxyalkanoates of various chemical composition synthesized on a complex carbon substrate by bacteria Cupriavidus eutrophus В10646 have been investigated. Two-, three-, and four-component copolymer samples have different sets and ratios of monomers with various lengths of carbon chains: 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB), 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HH), 3-hydroxy-4-methyl valerate (3H4MV), and diethylene glycol (DEG). It has been shown that weight-average molar mass Мw and polydispersity vary in a wide range with no correlation existing with the composition of copolymer polyhydroxyalkanoates and that thermal stability is preserved in the temperature interval between the melting temperature and the thermal degradation temperature from 100 to 120–140°С. The composition and ratio of monomers most notably affect the degree of crystallinity of polyhydroxyalkanoates. Significant differences between the degrees of crystallinity of three- and four-component polyhydroxyalkanoates have been found for the first time. The degree of crystallinity for copolymers P(3HB/3HV/4HB) is 9–22%, and the degree of crystallinity for copolymers P(3HB/3HV/3HH) and P(3HB/3GV/3H4MV) is 41–63%; this value is close to the degree of crystallinity for diblock copolymers P(3HB)/DEG, which is 56–69%. For the four-component copolymers P(3HB/3GV/4HB/3HH), the degree of crystallinity is 30–41%. The values of Мw for the copolymers P(3HB/DEG) are inhomogeneous and the polymers contain fractions uneven with respect to molecular mass: a high-molecular-mass polymer (Мw from 2700 to 4900 kDa) and a low-molecular-mass polymer (Мw = 46–167 kDa). For the copolymers P(3HB)/DEG and P(3HB/3HV/3H4MV), two peaks are observed in the region of melting with the gap between these peaks being 4–20°С. All of the types of copolymer samples, regardless of the monomer ratio, show an increase in elongation at break against the background of a decrease in tensile stress and Young’s modulus, with these effects being pronounced to different extents. On the whole, the properties of multicomponent polyhydroxyalkanoates differ appreciably. © 2017, Pleiades Publishing, Ltd.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Plotnikov V.F., Shishatskaya E.I., Mironov P.V., Vasil'ev A.D.
Заглавие : Physicochemical properties of two-component polyhydroxyalkanoates [Poly(3HB/3HV)]
Колич.характеристики :9 с
Место публикации : Biofizika: MEZHDUNARODNAYA KNIGA, 2004. - Vol. 49, Is. 6. - P1038-1046. - ISSN 0006-3029
Примечания : Cited References: 21
Предметные рубрики: BACTERIAL POLYHYDROXYALKANOATES
POLYESTERS
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates--copolymers of hydroxybutyrate and hydroxyvalerate--structure--physicochemical properties
Аннотация: A series of two-component polyhydroxyalkanoates consisting of hydroxybutyrate and hydroxyvalerate monomer at different ratios were synthesized using the bacterium Ralstonia eutropha B5786. The properties of polyhydroxyalkanoates were compared with those of the homopolymer of hydroxybutyric acid by X-ray structure analysis, IR spectroscopy, differential scanning calorimetry, and viscosimetry. With an increase in the molar fraction of hydroxyvalerate, an equalization of the ratio of the crystalline and amorphous phases in the copolymer was observed. The degree of crystallinity of the polymer decreased from 70-80 to 45-50%; in the range of an increase in the hydroxyvalerate molar fraction from several to 25-30 mol %, the dependence was linear. The temperature characteristics, the melting temperature (T-m), and the degradation temperature (T-d) were lower in polyhydroxyalkanoates than in polyhydroxybutyrate, for which T-m and T-d were 168-170 and 260-265degreesC, respectively. In the copolymer, as the molar fraction of hydroxyvalerate grew, both parameters decreased. In the range of variation of monomer ratio studied, they decreased to 150-160 and 200-220degreesC, respectively. No distinct correlation between the composition of the polymer and its molecular mass was found.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Plotnikov V.F., Shishatskaya E.I., Mironov P.V., Vasil'ev A.D.
Заглавие : Physicochemical properties of two-component polyhydroxyalkanoates, 3-hydroxybutyrate-3-hydroxyvalerate copolymers
Место публикации : Biophysics. - 2004. - Vol. 49, Is. 6. - С. 934-942. - ISSN 00063509 (ISSN)
Ключевые слова (''Своб.индексиров.''): hydroxybutyrate-hydroxyvalerate copolymers--physicochemical properties--polyhydroxyalkanoates--structure--bacteria (microorganisms)--cupriavidus necator
Аннотация: A series of two-component polyhydroxyalkanoates composed of hydroxybutyrate-hydroxyvalerate copolymers with different monomer ratio was obtained with the use of bacteria Ralstonia eutropha B5786. The properties of the polyhydroxyalkanoates in comparison with the homopolymer of hydroxybutyric acid were studied by X-ray diffraction analysis, IR spectroscopy, differential thermal analysis, and viscometry. The ratio of crystalline to amorphous phase in the copolymers tends to unity with increasing hydroxyvalerate content. This is accompanied by a decrease in the degree of crystallinity of the copolymers from 70-80 to 45-50%, the dependence is virtually linear within the range, of hydroxyvalerate mole fraction from several to 25-30 mol%. Thermal characteristics, melting temperature (Tm) and decomposition temperature (Td), of the polyhydroxyalkanoate copolymers are lower than those for polyhydroxybutyrate, whose Tm and Td are 168-170 and 260-265В°C, respectively. Both parameters decrease to 150-160 and 200-220В°C, respectively, when the hydroxyvalerate mole fraction is raised. No distinct correlation between polymer composition and molecular weight has been revealed. Copyright В© 2004 by MAIK "Nauka/Interperiodica".
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Kiselev, Evgeniy G., Demidenko, Alexey V., Zhila, Natalia O., Nemtsev, Ivan V., Lukyanenko, Anna V.
Заглавие : Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass
Колич.характеристики :25 с
Коллективы : Project "Agropreparations of the new generation: a strategy of construction and realization" [075-15-2021-626]; State Assignment of the Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2022. - Vol. 14, Is. 1. - Ст.132. - ISSN 2073-4360(eISSN), DOI 10.3390/polym14010132
Примечания : Cited References:93. - This study was financially supported by Project "Agropreparations of the new generation: a strategy of construction and realization" (Agreement No. 075-15-2021-626) in accordance with Resolution No. 220 of the Government of the Russian Federation of 9 April 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning" (polymer synthesis, properties), and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (films production, surface properties).
Предметные рубрики: GLUCOSE-UTILIZING STRAIN
RALSTONIA-EUTROPHA
ASPERGILLUS-NIGER
ACID
Аннотация: One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains-C. necator B-10646 and R. eutropha B 5786 and B 8562-were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 degrees C followed by acid hydrolysis at 60 degrees C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100-120 degrees C difference between the T-melt and T-degr, prevailing of the crystalline phase over the amorphous one (C-x between 69 and 75%), and variations in weight average molecular weight (409-480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and epsilon-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology-finding widely available and inexpensive substrates.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sevastianov V.I., Perova N.V., Shishatskaya E.I., Kalacheva G.S., Volova T.G.
Заглавие : Production of purified polyhydroxyalkanoates (PHAs) for applications in contact with blood
Колич.характеристики :14 с
Место публикации : J. Biomater. Sci.-Polym. Ed.: VSP BV, 2003. - Vol. 14, Is. 10. - P1029-1042. - ISSN 0920-5063, DOI 10.1163/156856203769231547
Примечания : Cited References: 34
Предметные рубрики: BIODEGRADABLE POLYESTERS
POLYMERS
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates (phas)--polyhydroxybutyrate (phb)--poly(hydroxybutyrate-co-hydroxyvalerate) (phbv)--endotoxins--beta-hydroxy acids--hemocompatibility
Аннотация: Samples of olyhydroxyalkanoates (PHAs), polyhydroxybutyrate (PHB) and copolymers poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 4 and 18 mol% hydroxyvalerate, synthesized by the bacteria Ralstonia eutropha B5786, were investigated. PHA films in contact with blood did not activate the hemostasis system at the level of cell response, but they did activate the coagulation system and the complement reaction. To detect biologically-active components in the PHAs, a detailed analysis of the composition of the polymers was conducted. Gas chromatography-mass spectrometry revealed long-chain fatty acids (FAs) in the tested PHAs. Their total concentration in the polymer ranged from tenths of mol% to 2-3 mol%, depending on the purification method. C-16:0 constituted the largest proportion, up to 70%. Of the long-chain hydroxy acids, only beta-OH-C-14:0 was detected and it did not exceed 0.06 mol%. The analysis of the hemocompatibility properties of the PHAs purified by a specialized procedure, including the quantitative and morphological estimation of platelets adherent to the surface of polymer films, the plasma recalcification time and complement activation studies, indicated that PHB and PHBV can be used in contact with blood. It has been found out that the lipopolysaccharides of bacteria producing PHAs, which contain mostly long-chain hydroxy acids, can be the factor activating the hemostasis systems. Thus, the technology of PHA purification must satisfy rather stringent specific requirements.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sevastianov V.I., Perova N.V., Shishatskaya E.I., Kalacheva G.S., Volova T.G.
Заглавие : Production of purified polyhydroxyalkanoates (PHAs) for applications in contact with blood
Место публикации : Journal of Biomaterials Science, Polymer Edition. - 2003. - Vol. 14, Is. 10. - С. 1029-1042. - ISSN 09205063 (ISSN) , DOI 10.1163/156856203769231547
Ключевые слова (''Своб.индексиров.''): ?-hydroxy acids--endotoxins--hemocompatibility--poly(hydroxybutyrate-co-hydroxyvalerate) (phbv)--polyhydroxyalkanoates (phas)--polyhydroxybutyrate (phb)--bacterium lipopolysaccharide--carbon--complement--copolymer--hydroxyacid--long chain fatty acid--poly(3 hydroxybutyric acid)--polyhydroxyalkanoic acid--valeric acid derivative--adult--article--biofilm--biotechnology--blood analysis--blood clotting--blood compatibility--cell function--chemical analysis--chemical composition--complement activation--concentration (parameters)--controlled study--gas chromatography--hemostasis--human--human cell--mass spectrometry--micromorphology--nonhuman--priority journal--purification--quantitative analysis--sampling--synthesis--thrombocyte adhesion--wautersia eutropha--biocompatible materials--blood--blood coagulation tests--chromatography, gas--complement activation--cupriavidus necator--fatty acids--humans--platelet adhesiveness--polyesters--surface properties
Аннотация: Samples of olyhydroxyalkanoates (PHAs), polyhydroxybutyrate (PHB) and copolymers poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 4 and 18 mol% hydroxyvalerate, synthesized by the bacteria Ralstonia eutropha B5786, were investigated. PHA films in contact with blood did not activate the hemostasis system at the level of cell response, but they did activate the coagulation system and the complement reaction. To detect biologically-active components in the PHAs, a detailed analysis of the composition of the polymers was conducted. Gas chromatography-mass spectrometry revealed long-chain fatty acids (FAs) in the tested PHAs. Their total concentration in the polymer ranged from tenths of mol% to 2-3 mol%, depending on the purification method. C16:0 constituted the largest proportion, up to 70%. Of the long-chain hydroxy acids, only ?-OH-C14:0 was detected and it did not exceed 0.06 mol%. The analysis of the hemocompatibility properties of the PHAs purified by a specialized procedure, including the quantitative and morphological estimation of platelets adherent to the surface of polymer films, the plasma recalcification time and complement activation studies, indicated that PHB and PHBV can be used in contact with blood. It has been found out that the lipopolysaccharides of bacteria producing PHAs, which contain mostly long-chain hydroxy acids, can be the factor activating the hemostasis systems. Thus, the technology of PHA purification must satisfy rather stringent specific requirements.
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