Journal articles: 'Crosslinking (Polymerization) Gel electrophoresis'

1

Huh, MM, BP Schick, PK Schick, and RW Colman. "Covalent crosslinking of human coagulation factor V by activated factor XIII from guinea pig megakaryocytes and human plasma." Blood 71, no. 6 (June 1, 1988): 1693–702. http://dx.doi.org/10.1182/blood.v71.6.1693.1693.

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Abstract Coagulation factor V (FV) has been shown to be synthesized in both the liver and megakaryocytes. We now present evidence that FV can be covalently crosslinked by an enzyme originating from megakaryocytes to form polymeric multimers of factor V. The guinea pig megakaryocyte enzyme appears to be factor XIIIa since the FV-crosslinking activity (1) had an absolute requirement for Ca++, (2) was completely inhibited by iodoacetamide, 5,5′-dithiobis- (2-nitrobenzoic acid), p- chloromercuribenzene sulfonic acid, and N-ethylmaleimide, all known alkylators of the thiol group at the active site of the factor XIIIa, (3) was blocked by known pseudoamine donor substrates of factor XIIIa including dansylcadaverine and putrescine, and (4) could be directly demonstrated in the guinea pig megakaryocyte lysate by a specific activity staining procedure. No tranglutaminase was detected in guinea pig megakaryocytes in contrast to red cells and liver. A similar pattern of covalent crosslinking of human FV by purified activated human plasma factor XIII was also demonstrated. Analysis of the crosslinked products of FV formed by the guinea pig enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicates the formation of intermediate as well as higher molecular weight polymers, suggesting that the crosslinking is a stepwise polymerization process.

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Huh, MM, BP Schick, PK Schick, and RW Colman. "Covalent crosslinking of human coagulation factor V by activated factor XIII from guinea pig megakaryocytes and human plasma." Blood 71, no. 6 (June 1, 1988): 1693–702. http://dx.doi.org/10.1182/blood.v71.6.1693.bloodjournal7161693.

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Coagulation factor V (FV) has been shown to be synthesized in both the liver and megakaryocytes. We now present evidence that FV can be covalently crosslinked by an enzyme originating from megakaryocytes to form polymeric multimers of factor V. The guinea pig megakaryocyte enzyme appears to be factor XIIIa since the FV-crosslinking activity (1) had an absolute requirement for Ca++, (2) was completely inhibited by iodoacetamide, 5,5′-dithiobis- (2-nitrobenzoic acid), p- chloromercuribenzene sulfonic acid, and N-ethylmaleimide, all known alkylators of the thiol group at the active site of the factor XIIIa, (3) was blocked by known pseudoamine donor substrates of factor XIIIa including dansylcadaverine and putrescine, and (4) could be directly demonstrated in the guinea pig megakaryocyte lysate by a specific activity staining procedure. No tranglutaminase was detected in guinea pig megakaryocytes in contrast to red cells and liver. A similar pattern of covalent crosslinking of human FV by purified activated human plasma factor XIII was also demonstrated. Analysis of the crosslinked products of FV formed by the guinea pig enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicates the formation of intermediate as well as higher molecular weight polymers, suggesting that the crosslinking is a stepwise polymerization process.

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3

Naryzhny, Stanislav N., Leroi V. DeSouza, K. W. Michael Siu, and Hoyun Lee. "Characterization of the human proliferating cell nuclear antigen physico-chemical properties: aspects of double trimer stability." Biochemistry and Cell Biology 84, no. 5 (October 2006): 669–76. http://dx.doi.org/10.1139/o06-037.

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Its toroidal structure allows the proliferating cell nuclear antigen (PCNA) to wrap around and move along the DNA fiber, thereby dramatically increasing the processivity of DNA polymerization. PCNA is also involved in the regulation of a wide spectrum of other biological functions, including epigenetic inheritance. We have recently reported that mammalian PCNA forms a double trimer complex, which may be critically important in coordinating DNA replication and other cellular functions. To gain a better understanding of the stability of PCNA complexes, we characterized the physico-chemical properties of the PCNA structure by in vivo and in vitro approaches. The data obtained by gel filtration and nondenaturing gel electrophoresis of native PCNA molecules confirm our previous observations, obtained using formaldehyde crosslinking, in which PCNA exists in the cell as a double trimer. We have also found that optimal pH (pH 6.5–7.5) is critical for the stability of the PCNA structure. The presence or absence of ATP, dithiothreitol, and Mg2+ does not affect the stability of the PCNA trimer or double trimer. However, 0.02% SDS can effectively inhibit PCNA double trimer, but not single trimer, formation. Interestingly, glycerol and ammonium sulfate significantly destabilize both PCNA trimer and double trimer structures.

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Yoshida, Nobuhiko, Shingi Imaoka, Hajime Hirata, Michio Matsuda, and Shinji Asakura. "Heterozygous Abnormal Fibrinogen Osaka III with the Replacement of γ Arginine-275 by Histidine Has an Apparently Higher Molecular Weight γ-Chain Variant." Thrombosis and Haemostasis 68, no. 05 (1992): 534–38. http://dx.doi.org/10.1055/s-0038-1646313.

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SummaryCongenitally abnormal fibrinogen Osaka III with the replacement of γ Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of α- and γ-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal γ-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 γ remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethy-lenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).

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Yoshida, N., M. Okuma, M. Moroi, and M. Matsuda. "A lower molecular weight gamma-chain variant in a congenital abnormal fibrinogen (Kyoto)." Blood 68, no. 3 (September 1, 1986): 703–7. http://dx.doi.org/10.1182/blood.v68.3.703.703.

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Abstract A gamma-chain variant with a lower molecular weight than the normal gamma chain was detected in a new congenital abnormal fibrinogen with impaired polymerization of the fibrin monomer and with normal release of fibrinopeptides A and B in a 45-year-old male. Purified fibrinogen analyzed on SDS-polyacrylamide gel electrophoresis under the reduced condition contained an abnormal protein band with an apparent molecular weight of 48,000 compared with the gamma chain with a molecular weight of 50,000. This abnormal protein band was found to be a gamma-chain variant from the molar ratio of A alpha chain:B beta chain:gamma chain:abnormal protein (about 2:2:1:1), with positive staining for carbohydrate and crosslinking ability. Crosslinked fibrin contained three types of gamma-gamma dimers with apparent molecular weights of 94,000 (the same as normal major gamma-gamma dimer), 92,000 and 90,000, and the plasmic digests of crosslinked fibrin in the presence of calcium retained three types of gamma-gamma dimer remnants. This suggests that the abnormal gamma-chain variant has a shorter polypeptide chain not in the NH2-terminal but in the COOH-terminal portion, probably at or near the polymerization site. This patient's two daughters had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Kyoto, and the gamma- chain variant as gamma Kyoto.

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Yoshida, N., M. Okuma, M. Moroi, and M. Matsuda. "A lower molecular weight gamma-chain variant in a congenital abnormal fibrinogen (Kyoto)." Blood 68, no. 3 (September 1, 1986): 703–7. http://dx.doi.org/10.1182/blood.v68.3.703.bloodjournal683703.

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A gamma-chain variant with a lower molecular weight than the normal gamma chain was detected in a new congenital abnormal fibrinogen with impaired polymerization of the fibrin monomer and with normal release of fibrinopeptides A and B in a 45-year-old male. Purified fibrinogen analyzed on SDS-polyacrylamide gel electrophoresis under the reduced condition contained an abnormal protein band with an apparent molecular weight of 48,000 compared with the gamma chain with a molecular weight of 50,000. This abnormal protein band was found to be a gamma-chain variant from the molar ratio of A alpha chain:B beta chain:gamma chain:abnormal protein (about 2:2:1:1), with positive staining for carbohydrate and crosslinking ability. Crosslinked fibrin contained three types of gamma-gamma dimers with apparent molecular weights of 94,000 (the same as normal major gamma-gamma dimer), 92,000 and 90,000, and the plasmic digests of crosslinked fibrin in the presence of calcium retained three types of gamma-gamma dimer remnants. This suggests that the abnormal gamma-chain variant has a shorter polypeptide chain not in the NH2-terminal but in the COOH-terminal portion, probably at or near the polymerization site. This patient's two daughters had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Kyoto, and the gamma- chain variant as gamma Kyoto.

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Yoshida, N., K. Ota, M. Moroi, and M. Matsuda. "An apparently higher molecular weight gamma-chain variant in a new congenital abnormal fibrinogen Tochigi characterized by the replacement of gamma arginine-275 by cysteine." Blood 71, no. 2 (February 1, 1988): 480–87. http://dx.doi.org/10.1182/blood.v71.2.480.480.

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Abstract A gamma-chain variant with an apparently higher molecular weight than the normal gamma-chain was detected in a new congenital abnormal fibrinogen with impaired polymerization of the fibrin monomer and with normal release of fibrinopeptides A and B in a 51-year-old male. Purified fibrinogen analyzed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under the reduced condition in the system of Laemmli contained two protein bands in the gamma-chain region (molecular weight, 50,500 as compared with 50,000 for the normal), both with normal crosslinking ability. The presence of two types of gamma- chains was more clearly detected when reduced and carboxymethylated fibrinogen was analyzed by SDS-PAGE or when reduced fragment D2 was analyzed on SDS-PAGE followed by Western blotting, and identified by positive staining for anti gamma-chain monoclonal antibody. Cyanogen bromide- or lysylendopeptidase-cleavage of purified gamma-chains analyzed on reverse-phase high performance liquid chromatography showed the decrease of one peptide compared with the normal and the appearance of an abnormal peptide peak. Amino acid sequence analysis demonstrated that the gamma arginine-275 of gamma-chain variant was replaced by a cysteine. These data suggest that some regions or conformations containing gamma 275 will affect the polymerization of fibrin monomers. The propositus' two daughters had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Tochigi, and the gamma-chain variant as gamma Tochigi.

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8

Yoshida, N., K. Ota, M. Moroi, and M. Matsuda. "An apparently higher molecular weight gamma-chain variant in a new congenital abnormal fibrinogen Tochigi characterized by the replacement of gamma arginine-275 by cysteine." Blood 71, no. 2 (February 1, 1988): 480–87. http://dx.doi.org/10.1182/blood.v71.2.480.bloodjournal712480.

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A gamma-chain variant with an apparently higher molecular weight than the normal gamma-chain was detected in a new congenital abnormal fibrinogen with impaired polymerization of the fibrin monomer and with normal release of fibrinopeptides A and B in a 51-year-old male. Purified fibrinogen analyzed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under the reduced condition in the system of Laemmli contained two protein bands in the gamma-chain region (molecular weight, 50,500 as compared with 50,000 for the normal), both with normal crosslinking ability. The presence of two types of gamma- chains was more clearly detected when reduced and carboxymethylated fibrinogen was analyzed by SDS-PAGE or when reduced fragment D2 was analyzed on SDS-PAGE followed by Western blotting, and identified by positive staining for anti gamma-chain monoclonal antibody. Cyanogen bromide- or lysylendopeptidase-cleavage of purified gamma-chains analyzed on reverse-phase high performance liquid chromatography showed the decrease of one peptide compared with the normal and the appearance of an abnormal peptide peak. Amino acid sequence analysis demonstrated that the gamma arginine-275 of gamma-chain variant was replaced by a cysteine. These data suggest that some regions or conformations containing gamma 275 will affect the polymerization of fibrin monomers. The propositus' two daughters had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Tochigi, and the gamma-chain variant as gamma Tochigi.

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9

Quarless, Shelley A., and Charles R. Cantor. "Analysis of RNA structure by ultraviolet crosslinking and denaturation gel electrophoresis." Analytical Biochemistry 147, no. 2 (June 1985): 296–300. http://dx.doi.org/10.1016/0003-2697(85)90275-1.

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10

Ida, Shohei, Akimitsu Katsurada, Mitsuhiro Tsujio, Motoharu Nakamura, and Yoshitsugu Hirokawa. "Crosslinker-Based Regulation of Swelling Behavior of Poly(N-isopropylacrylamide) Gels in a Post-Polymerization Crosslinking System." Gels 6, no. 1 (December 21, 2019): 2. http://dx.doi.org/10.3390/gels6010002.

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A fundamental understanding of the effect of a crosslinker on gel properties is important for the design of novel soft materials because a crosslinking is a key component of polymer gels. We focused on post-polymerization crosslinking (PPC) system utilizing activated ester chemistry, which is a powerful tool due to structural diversity of diamine crosslinkers and less susceptibility to solvent effect compared to conventional divinyl crosslinking system, to systematically evaluate the crosslinker effect on the gel properties. A variety of alkyldiamine crosslinkers was employed for the synthesis of poly(N-isopropylacrylamide) (PNIPAAm) gels and it was clarified that the length of alkyl chains of diamine crosslinkers strongly affected the gelation reaction and the swelling behavior. The longer crosslinker induced faster gelation and decreased the swelling degree and the response temperature in water, while the crosslinking density did not significantly change. In addition, we were able to modify the polymer chains in parallel with crosslinking by using a monoamine modifier along with a diamine crosslinker. This simultaneous chain modification during crosslinking (SMC) was demonstrated to be useful for the regulation of the crosslinking density and the swelling behavior of PNIPAAm gels.

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Han, Dong, Xingxiao Li, Jing Peng, Ling Xu, Jiuqiang Li, Huibo Li, and Maolin Zhai. "A new imidazolium-based polymeric ionic liquid gel with high adsorption capacity for perrhenate." RSC Advances 6, no. 73 (2016): 69052–59. http://dx.doi.org/10.1039/c6ra12239f.

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Wang, Zhidan, Jie Wu, Xiaoyu Shi, Fei Song, Wenli Gao, and Shouxin Liu. "Stereocomplexation of Poly(lactic acid) and Chemical Crosslinking of Ethylene Glycol Dimethacrylate (EGDMA) Double-Crosslinked Temperature/pH Dual Responsive Hydrogels." Polymers 12, no. 10 (September 25, 2020): 2204. http://dx.doi.org/10.3390/polym12102204.

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Physical crosslinking and chemical crosslinking were used to further improve the mechanical properties and stability of the gel. A temperature/pH dual sensitive and double-crosslinked gel was prepared by the stereo-complex of HEMA-PLLA20 and HEMA-PDLA20 as a physical crosslinking agent, ethylene glycol dimethacrylate (EGDMA) as a chemical crosslinking agent, and azodiisobutyronitrile (AIBN) as an initiator for free radical polymerization. This paper focused on the performance comparison of chemical crosslinked gel, a physical crosslinked gel, and a dual crosslinked gel. The water absorption, temperature, and pH sensitivity of the three hydrogels were studied by a scanning electron microscope (SEM) and swelling performance research. We used a thermal analysis system (TGA) and dynamic viscoelastic spectrometer to study thermal properties and mechanical properties of these gels. Lastly, the in vitro drug release behavior of double-crosslinked hydrogel loaded with doxorubicin under different conditions was studied. The results show that the double-crosslinked and temperature/pH dual responsive hydrogels has great mechanical properties and good stability.

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Ahagon, Asahiro. "Molecular Weight Defined in Sol-Gel Analysis and Its Application to Evaluate Branching." Rubber Chemistry and Technology 68, no. 2 (May 1, 1995): 287–96. http://dx.doi.org/10.5254/1.3538743.

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Abstract It is considered that many “linear” polymers are actually branched; however, it is difficult to show this with ordinary methods for an arbitrarily chosen polymer. Branching can be regarded as premature crosslinking below the gel point. Attention is then paid to the well-established Charlesby-Pinner Equation used for sol-gel analysis in crosslinking studies. It contains the number average degree of polymerization before crosslinking as a parameter. The molecular parameter is considered here to be that of the virtual linear polymer which would be obtained by unlinking any branch points contained in the polymer. Evidence is shown to support this. It is then possible to estimate the total number of linear components on an average molecule of a branched polymer by taking the ratio of the number average molecular weight measured by two methods, i.e., sol-gel analysis and an ordinary method like GPC. Further information about the branching structure can be obtained by additional measurements of effective crosslink density for a series of polymers obtained from similar polymerization processes.

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Rapp, Tracey L., Will K. Kowalchyk, Kevin L. Davis, Elizabeth A. Todd, Kei Lee Liu, and Michael D. Morris. "Acrylamide polymerization kinetics in gel electrophoresis capillaries. A Raman microprobe study." Analytical Chemistry 64, no. 20 (October 15, 1992): 2434–37. http://dx.doi.org/10.1021/ac00044a023.

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Liu, Qun Feng, Bo Yuan, and Xiao Feng Chen. "A Simple Method to Synthese PNIPAM Hydrogel with Improved Response Rate by Conventional Radical Crosslinking Polymerization." Advanced Materials Research 236-238 (May 2011): 1483–86. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1483.

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A kind of poly(N-isopropylacrylamide) (PNIPAM) gel was synthesized by radical polymerization of N-isopropylacrylamide monomer in the present of crosslinker N,N-Methylenebisacylamide using short reaction time. This kind of PNIPAM gel exhibits higher swelling ratio at low temperature and much faster deswelling rate than conventional gel, which could be attributed to the presence of loops, dangling chains and other incomplete structure in the gel caused by short reaction time.

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Tarasova, Natalia, Alexey Zanin, Efrem Krivoborodov, Ilya Toropygin, Ekaterina Pascal, and Yaroslav Mezhuev. "The New Approach to the Preparation of Polyacrylamide-Based Hydrogels: Initiation of Polymerization of Acrylamide with 1,3-Dimethylimidazolium (Phosphonooxy-)Oligosulphanide under Drying Aqueous Solutions." Polymers 13, no. 11 (May 30, 2021): 1806. http://dx.doi.org/10.3390/polym13111806.

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The new initiator of the polymerization of acrylamide, leading to the formation of crosslinked polyacrylamide, was discovered. The structure of the synthesized polyacrylamide was characterized by XRD, 1H NMR, and 13C NMR spectroscopy. It was shown that 1,3-dimethylimidazolium (phosphonooxy-)oligosulphanide is able to initiate radical polymerization under drying aqueous solutions of acrylamide, even at room temperature. According to XRF data, the synthesized polyacrylamide gel contains 0.28 wt% of sulphur. The formed polymer network has a low crosslinking density and a high equilibrium degree of swelling. The swelling rate of polyacrylamide gel in water corresponds to the first order kinetic equation with the rate constant 6.2 × 10−2 min−1. The initiator is promising for combining acrylamide polymerization with the processes of gel molding and drying.

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Thompson, Michelle A., John C. Ford, and George R. Long. "On-Line Detection in Slab Gel Electrophoresis Using Thermal Lens Spectrophotometry." Applied Spectroscopy 46, no. 6 (June 1992): 945–47. http://dx.doi.org/10.1366/0003702924124556.

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Thermal lens spectrophotometry was used to detect hemoglobin and cytochrome c within an acrylamide gel matrix both during electrophoresis and in static experiments in which each protein was incorporated in the matrix during polymerization. For cytochrome c, the detection limit was 0.02 mg/mL for static experiments (approximately 0.5 ng in the laser beam volume), while a detection limit of 180 ng (5 ng in the beam volume) was found for electrophoresis runs.

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Sung, Jungmoon, Dong Geun Lee, Sukchin Lee, Junyoung Park, and Hyun Wook Jung. "Crosslinking Dynamics and Gelation Characteristics of Photo- and Thermally Polymerized Poly(Ethylene Glycol) Hydrogels." Materials 13, no. 15 (July 23, 2020): 3277. http://dx.doi.org/10.3390/ma13153277.

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The crosslinking behaviors and gelation features of poly(ethylene glycol) (PEG) hydrogels were scrutinized during the UV and thermal polymerizations of mixtures of poly(ethylene glycol) methacrylate (PEGMA, monomer) and poly(ethylene glycol) dimethacrylates (PEGDMAs, crosslinkers). The real-time crosslinking behavior of the PEG hydrogels was quantified as a function of the UV irradiation time and reaction temperature during the UV and thermal polymerization, respectively, using real-time FT-IR spectrometry and rotational rheometry. The gelation characteristics of UV- and thermally crosslinked hydrogels were compared through the analysis of the gel fraction, swelling ratio, surface hardness, and the loading and release of rhodamine-B. The gelation properties of the cured hydrogel films were suitably correlated with the real-time rheological properties and crosslinked network state of the PEG mixtures. The crosslinking and gelation properties of the cured hydrogels could be optimally tuned by not only the molecular weight of the crosslinker but also the UV or thermal polymerization conditions.

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Chiari, Marcella, Claudia Micheletti, Pier Giorgio Righetti, and Giovanni Poli. "Polyacrylamide gel polymerization under non-oxidizing conditions, as monitored by capillary zone electrophoresis." Journal of Chromatography A 598, no. 2 (May 1992): 287–97. http://dx.doi.org/10.1016/0021-9673(92)85058-2.

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20

Dušek, Karel. "Special Features of Network Formation by Chain Crosslinking Copolymerization." Collection of Czechoslovak Chemical Communications 58, no. 10 (1993): 2245–65. http://dx.doi.org/10.1135/cccc19932245.

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Special features of free-radical crosslinking copolymerization and the structure of the resulting products have been reviewed. Characteristic is the effect of spatial correlations on the apparent reactivity of pendant double bonds. These correlation make the apparent reactivity in the course of copolymerization to increase (cyclization) and decrease (steric hindrances). At intermediate and higher concentrations of the crosslinker, compact structures are formed which are internally crosslinked. Only pendant double bonds in the peripheral layer are able to take part in polymerization reactions whereas the internal ones cannot react. The state of theoretical simulations of this structure growth is discussed with a special emphasis on the development of the kinetic (coagulation) network formation theories so that the above mentioned features may be taken into account. Also, the important role of the presence of a diluent during polymerization id discussed. It can result in a change of network chain conformations necessary for networks exhibiting volume phase transitions. Alternatively, it can induce liquid-gel phase separations resulting in inhomogeneous networks having a variety of morphologies.

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Dooley, Steven, Cornelius Welter, and Nikolaus Blin. "DNA-protein interaction analysis using polyacrylamide gel electrophoresis and a simple and sensitive UV crosslinking procedure." Electrophoresis 13, no. 1 (1992): 333–34. http://dx.doi.org/10.1002/elps.1150130166.

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Rice, K. G., M. K. Rottink, and R. J. Linhardt. "Fractionation of heparin-derived oligosaccharides by gradient polyacrylamide-gel electrophoresis." Biochemical Journal 244, no. 3 (June 15, 1987): 515–22. http://dx.doi.org/10.1042/bj2440515.

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Heparin-derived oligosaccharides, prepared by using flavobacterial heparinase, having a high degree of heterogeneity (sequence variability) were resolved into sharp well-defined bands by using polyacrylamide gel electrophoresis (PAGE). The use of a stacking gel and a high-density-pore-gradient resolving gel was primarily responsible for the success of this separation. Low-Mr standards of known structure and having a degree of polymerization (dp) 2-6 were used to establish that the separation on gradient PAGE was primarily dependent on molecular size. High-Mr oligosaccharides (dp 8-20) were prepared using strong-anion-exchange h.p.l.c. and were used to help characterize the gradient PAGE separation. Kinetic profiles were obtained for the depolymerization of heparin and heparan sulphate with heparinase and heparitinase respectively. The utility of this approach in sequencing oligosaccharides derived from glycosaminoglycans is discussed.

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Reed, Guy L., Gary R. Matsueda, and Edgar Haber. "Platelet Factor XIII Increases the Fibrinolytic Resistance of Platelet-Rich Clots by Accelerating the Crosslinking of α2-Antiplasmin to Fibrin." Thrombosis and Haemostasis 68, no. 03 (1992): 315–20. http://dx.doi.org/10.1055/s-0038-1656372.

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SummaryPlatelet clots resist fibrinolysis by plasminogen activators. We hypothesized that platelet factor XIII may enhance the fibrinolytic resistance of platelet-rich clots by catalyzing the crosslinking of α2-antiplasmin (α2AP) to fibrin. Analysis of plasma clot structure by polyacrylamide gel electrophoresis and immunoblotting revealed accelerated α2AP-fibrin crosslinking in platelet-rich compared with platelet-depleted plasma clots. A similar study of clots formed with purified fibrinogen (depleted of factor XIII activity), isolated platelets, and specific factor XIII inhibitors indicated that this accelerated crosslinking was due to the catalytic activity of platelet factor XIII. Moreover, when washed platelets were aggregated by thrombin, there was evidence of platelet factor XIII-mediated crosslinking between platelet α2AP and platelet fibrin(ogen). Specific inhibition (by a monoclonal antibody) of the α2AP associated with washed platelet aggregates accelerated the fibrinolysis of the platelet aggregate. Thus in platelet-rich plasma clots, and in thrombin-induced platelet aggregates, platelet factor XIII actively formed α2AP-fibrin crosslinks, which appeared to enhance the resistance of platelet-rich clots to fibrinolysis.

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Radu, Anita Laura, Ana Mihaela Gavrila, Bogdan Cursaru, Catalina Paula Spatarelu, Teodor Sandu, Andrei Sarbu, Mircea Teodorescu, Francois Xavier Perrin, Tanta Verona Iordache, and Anamaria Zaharia. "Poly(ethylene Glycol) Diacrylate-Nanogels Synthesized by Mini-emulsion Polymerization." Materiale Plastice 56, no. 3 (September 30, 2019): 514–19. http://dx.doi.org/10.37358/mp.19.3.5220.

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New nanogels (NGs) with tailored properties were obtained using a mini-emulsion technique, from poly(ethylene glycol) diacrylate (PEGDA) self-crosslinking macromers of various molecular weight. By modifying synthesis parameters (hydrophilic-lipophilic balance, emulsifier and the ratio of organic-aqueous medium), optimum recipes of NGs were selected. Therefore, the molecular weight distribution and the functionalization degree of the PEGDA2000 macromer were assessed by Gel Permeation Chromatography (GPC) and Nuclear Magnetic Resonance (NMR), respectively. Furthermore, the PEGDA-NGs were investigated by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) for size distributions and morphology. DLS and TEM results confirm that these new PEGDA-NGs hold potential for biomedical applications.

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Rosenmund, A., C. Kuyas, and A. Haeberli. "Oxidative radioiodination damage to human lactoferrin." Biochemical Journal 240, no. 1 (November 15, 1986): 239–45. http://dx.doi.org/10.1042/bj2400239.

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Oxidative iodination of human lactoferrin (Lf) as commonly performed by using the chloramine-T, the Iodogen or the lactoperoxidase method produces an unreliable tracer protein because of excessive and heterogeneous polymer formation. Before iodination a minor tetramer fraction may be demonstrable in iron-saturated Lf only. Iodination-induced polymerization of iron-poor as well as iron-saturated Lf occurs independently of the presence or absence of 10 mM-EDTA and the 125I-/Lf molar ratio used for iodination. 125I-Lf polymers are mainly covalently linked, as suggested by the lack of substantial dissociation in SDS/polyacrylamide-gel electrophoresis. Damage to the 125I-Lf monomer may be another consequence of oxidative iodination. This is demonstrated in SDS/polyacrylamide-gel electrophoresis where 50% of the radioactivity of apparently normal monomer (Mr 75,000) is displaced to a lower-Mr region (30,000-67,000) after reduction with dithiothreitol. Non-oxidative iodination by the Bolton-Hunter technique produces an antigenetically stable tracer that is not being subjected to polymerization and monomer degradation as judged by high-performance gel chromatography and SDS/polyacrylamide-gel electrophoresis with and without dithiothreitol treatment. It is concluded that oxidation in itself leads to covalent non-disulphide cross-linking between human Lf molecules and, possibly, to intramolecular peptide-bond breaking becoming unmasked under reducing conditions. In biological experiments with human 125I-Lf this problem should be carefully considered.

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Kim, Jung Soo, Dong Hyun Kim, and Youn Suk Lee. "The Influence of Monomer Composition and Surface-CrossLinking Condition on Biodegradation and Gel Strength of Super Absorbent Polymer." Polymers 13, no. 4 (February 23, 2021): 663. http://dx.doi.org/10.3390/polym13040663.

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In this study, a superabsorbent polymer (SAP) comprising poly (IA-co-cellulose-co-VSA-co-AA; ICVA) core-SAP (CSAP) was synthesized through radical polymerization using itaconic acid (IA), acrylic acid (AA), cellulose, and vinyl sulfonic acid (VSA) as monomers. The absorption performances and relative biodegradability of various compositions prepared by adjusting the amounts of cellulose and VSA with constant IA and AA content were compared. Increasing the cellulose content in CSAP contributed to improved biodegradation of the surface-crosslinked SAP (SSAP) and gel strength, although the free absorbency (FA) and centrifuge retention capacity (CRC) decreased. Increasing the VSA content resulted in strong anionicity, which enables the absorption of large amounts of water. Surface-crosslinking technology was applied to the CSAP synthesized with the optimal composition ratio to increase its absorption performance and gel strength. Improved performance of the synthesized SSAP (a CRC of 30.4 g/g, absorbency under load (AUL) of 23.3 g/g, and permeability of 55 s) was achieved by selecting the optimal surface-crosslinking treatment time and the amount of distilled water in the surface-crosslinking solution: as the latter was increased in the surface-crosslinking solution, the AUL and permeability of the SSAP were improved, and its biodegradability was found to be 54% compared to the 100% biodegradable cellulose hydrogel in the control group.

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Gai, Jing-Gang, Shi-Peng Zhu, Jian Kang, Ya Cao, and Ming Xiang. "Effects of Polymerization and Crosslinking Technologies on the Crystallization Behaviors and Gel Network of Crosslinked Polyethylene." Journal of Macromolecular Science, Part B 51, no. 7 (December 28, 2011): 1322–34. http://dx.doi.org/10.1080/00222348.2011.629900.

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PEDERSEN, Katrine E., Anja P. EINHOLM, Anni CHRISTENSEN, Lotte SCHACK, Troels WIND, John M. KENNEY, and Peter A. ANDREASEN. "Plasminogen activator inhibitor-1 polymers, induced by inactivating amphipathic organochemical ligands." Biochemical Journal 372, no. 3 (June 15, 2003): 747–55. http://dx.doi.org/10.1042/bj20021868.

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Negatively charged organochemical inactivators of the anti-proteolytic activity of plasminogen activator inhibitor-1 (PAI-1) convert it to inactive polymers. As investigated by native gel electrophoresis, the size of the PAI-1 polymers ranged from dimers to multimers of more than 20 units. As compared with native PAI-1, the polymers exhibited an increased resistance to temperature-induced unfolding. Polymerization was associated with specific changes in patterns of digestion with non-target proteases. During incubation with urokinase-type plasminogen activator, the polymers were slowly converted to reactive centre-cleaved monomers, indicating substrate behaviour of the terminal PAI-1 molecules in the polymers. A quadruple mutant of PAI-1 with a retarded rate of latency transition also had a retarded rate of polymerization. Studying a number of serpins by native gel electrophoresis, ligand-induced polymerization was observed only with PAI-1 and heparin cofactor II, which were also able to copolymerize. On the basis of these results, we suggest that the binding of ligands in a specific region of PAI-1 leads to so-called loop–sheet polymerization, in which the reactive centre loop of one molecule binds to β-sheet A in another molecule. Induction of serpin polymerization by small organochemical ligands is a novel finding and is of protein chemical interest in relation to pathological protein polymerization in general.

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Benavides, R., L. W. Oenning, M. M. S. Paula, L. Da Silva, and C. Kotzian. "Use of a TrI-functional Crosslinking Agent in Styrene/Acrylic Acid Copolymers to Enhance Mechanical Properties for use as Membranes in Fuel Cells." Journal of New Materials for Electrochemical Systems 16, no. 3 (July 4, 2013): 157–62. http://dx.doi.org/10.14447/jnmes.v16i3.5.

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Alternative copolymers to the well-known Nafion membranes are the styrene/acrylic acid PS/AA) copolymers, which have advantages in cost and availability of raw materials. Previous attempts to improve their mechanical properties involved crosslinking with divinyl benzene, but in this case the use of the tri-functional monomer TMPTMA (trimethylol propane trimethacrylate) is examined. Copolymers with a PS/AA molar ratio of 94/6 were prepared by a free radical polymerization reaction, including TMPTMA at 0.1, 0.01 and 0.001 % mol concentrations. Reactions were followed by percentage yield (gravimetry), Infrared spectroscopy (FTIR) and extent of crosslinking by gel percentage evaluation (soxhlet extraction) with three different solvents (water, tetrahydrofuran and dichloromethane). Thermal transitions were followed by calorimetry (DSC), stability by thermogravimetry (TGA) and mechanical properties by dynamic mechanical analysis (DMA). FTIR spectra show typical bands from the copolymer while the corresponding bands associated with crosslinking are overlapped; however, gel percentage evaluations show a higher level of crosslinking for the 0.1% TMPTMA copolymer and lack of solubility in water. DSC thermograms indicate an increment in the glass transition (Tg) and TGA exhibits a small increment in thermal stability for the crosslinked copolymers. Elastic moduli suggests a rubbery material for TMPTMA crosslinked copolymers while loss modulus confirms a Tg enhancement as observed by DSC. A 0.1 % TMPTMA copolymer does not form a membrane due to its insolubility and infusibility.

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Kornberg, A., CW Francis, and VJ Marder. "Plasma crosslinked fibrin polymers: quantitation based on tissue plasminogen activator conversion to D-dimer and measurement in normal and patients with acute thrombotic disorders." Blood 80, no. 3 (August 1, 1992): 709–17. http://dx.doi.org/10.1182/blood.v80.3.709.709.

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Abstract Plasma crosslinked fibrin polymers (XLFP) are formed as a result of in vivo hemostatic activation and are elevated in thrombotic disease. We have investigated the plasmic degradation of plasma XLFP in vitro to provide information regarding the pattern of crosslinking and the composition of degradation products. Plasma XLFP were identified by sodium dodecyl sulfate (SDS)-agarose electrophoresis and Western blotting and quantitated by gel scanning. D-dimer was measured by enzyme-linked immunosorbent assay and the results were verified by SDS- polyacrylamide gel electrophoresis and Western blotting of the digests. Complete degradation of XLFP occurred only after supplementation of plasma with plasminogen (5 U/mL) and incubation with recombinant tissue plasminogen activator (rt-PA), indicating that the normal plasma plasminogen concentration limits plasmic degradation in vitro. Gel electrophoresis showed that the principal terminal degradation products of XLDP were fragments D, DD, and E, indicating that crosslinking occurred primarily through gamma chain dimers. After adding a low concentration of thrombin to plasma in vitro, XLFP increased progressively before clotting, and the concentration correlated with the increase in the D-dimer concentration after degradation (r = .98). Plasma XLFP and D-dimer concentrations in plasmic digests were significantly elevated in patients with stroke (150 +/- 83 micrograms/mL and 88 +/- 32 micrograms/mL), myocardial infarction (217 +/- 110 micrograms/mL and 84 +/- 30 micrograms/mL), and venous thrombosis (187 +/- 80 micrograms/mL and 86 +/- 19 micrograms/mL) compared with normals (28 +/- 12 micrograms/mL and 25 +/- 7 micrograms/mL). There was a strong correlation between the plasma concentration of XLFP and the D-dimer immunoreactivity of plasma after plasmic degradation (r = .87). The results indicate that XLFP in plasma are crosslinked primarily through gamma chains and degrade to fragment DD with plasminogen activation. Also, the immunoreactivity of in vitro plasmic digests of plasma reflects the concentration of XLFP and may provide a useful indirect measure of in vivo hemostatic activation in patients with thrombotic disease.

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Kornberg, A., CW Francis, and VJ Marder. "Plasma crosslinked fibrin polymers: quantitation based on tissue plasminogen activator conversion to D-dimer and measurement in normal and patients with acute thrombotic disorders." Blood 80, no. 3 (August 1, 1992): 709–17. http://dx.doi.org/10.1182/blood.v80.3.709.bloodjournal803709.

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Plasma crosslinked fibrin polymers (XLFP) are formed as a result of in vivo hemostatic activation and are elevated in thrombotic disease. We have investigated the plasmic degradation of plasma XLFP in vitro to provide information regarding the pattern of crosslinking and the composition of degradation products. Plasma XLFP were identified by sodium dodecyl sulfate (SDS)-agarose electrophoresis and Western blotting and quantitated by gel scanning. D-dimer was measured by enzyme-linked immunosorbent assay and the results were verified by SDS- polyacrylamide gel electrophoresis and Western blotting of the digests. Complete degradation of XLFP occurred only after supplementation of plasma with plasminogen (5 U/mL) and incubation with recombinant tissue plasminogen activator (rt-PA), indicating that the normal plasma plasminogen concentration limits plasmic degradation in vitro. Gel electrophoresis showed that the principal terminal degradation products of XLDP were fragments D, DD, and E, indicating that crosslinking occurred primarily through gamma chain dimers. After adding a low concentration of thrombin to plasma in vitro, XLFP increased progressively before clotting, and the concentration correlated with the increase in the D-dimer concentration after degradation (r = .98). Plasma XLFP and D-dimer concentrations in plasmic digests were significantly elevated in patients with stroke (150 +/- 83 micrograms/mL and 88 +/- 32 micrograms/mL), myocardial infarction (217 +/- 110 micrograms/mL and 84 +/- 30 micrograms/mL), and venous thrombosis (187 +/- 80 micrograms/mL and 86 +/- 19 micrograms/mL) compared with normals (28 +/- 12 micrograms/mL and 25 +/- 7 micrograms/mL). There was a strong correlation between the plasma concentration of XLFP and the D-dimer immunoreactivity of plasma after plasmic degradation (r = .87). The results indicate that XLFP in plasma are crosslinked primarily through gamma chains and degrade to fragment DD with plasminogen activation. Also, the immunoreactivity of in vitro plasmic digests of plasma reflects the concentration of XLFP and may provide a useful indirect measure of in vivo hemostatic activation in patients with thrombotic disease.

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Liu, Chang, Amit K. Tripathi, Wei Gao, and John G. Tsavalas. "Crosslinking in Semi-Batch Seeded Emulsion Polymerization: Effect of Linear and Non-Linear Monomer Feeding Rate Profiles on Gel Formation." Polymers 13, no. 4 (February 17, 2021): 596. http://dx.doi.org/10.3390/polym13040596.

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Waterborne latex is often called a product-of-process. Here, the effect of semi-batch monomer feed rate on the kinetics and gel formation in seeded emulsion polymerization was investigated for the copolymerization of n-butyl methacrylate (n-BMA) and ethylene glycol dimethacrylate (EGDMA). Strikingly, the gel fraction was observed to be significantly influenced by monomer feed rate, even while most of the experiments were performed under so-called starve-fed conditions. More flooded conditions from faster monomer feed rates, including seeded batch reactions, counterintuitively resulted in significantly higher gel fraction. Chain transfer to polymer was intentionally suppressed here via monomer selection so as to focus mechanistic insights to relate only to the influence of a divinyl monomer, as opposed to being clouded by contributions to topology from long chain branching. Simulations revealed that the dominant influence on this phenomenon was the sensitivity of primary intramolecular cyclization to the instantaneous unreacted monomer concentration, which is directly impacted by monomer feed rate. The rate constant for cyclization for these conditions was determined to be first order and 4000 s−1, approximately 4 times that typically observed for backbiting in acrylates. This concept has been explored previously for bulk and solution polymerizations, but not for emulsified reaction environments and especially for the very low mole fraction divinyl monomer. In addition, while gel fraction could be dramatically manipulated by variations in linear monomer feed rates, it could be markedly enhanced by leveraging non-linear feed profiles built from combination sequences of flooded and starved conditions. For a 2 h total feed time, a fully linear profile resulted in 30% gel while a corresponding non-linear profile with an early fast-feed segment resulted in 80% gel.

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Ahagon, Asahiro. "Evaluation of Chain Scission during Mixing of Filled Compounds." Rubber Chemistry and Technology 69, no. 5 (November 1, 1996): 742–51. http://dx.doi.org/10.5254/1.3538398.

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Abstract Whether chain scission takes place during mixing of black-filled compounds has been a debatable subject which is yet unsettled. The uncertainty originates from the material system which contains gel. A direct method to evaluate scission is to quantify the change in the number of chain ends, since two chain ends will be newly created on each event of scission. It requires determination of an average molecular weight of the linear components which constitute the gel-containing system. The degree of polymerization denned in the Charlesby-Pinner theory, derived for crosslinking study by means of sol-gel analysis, could be conveniently used for the purpose. The theory, however, cannot be directly applied for black-filled compounds because the composite structure in the compounds does not allow one to satisfy the assumptions made in the theory, i.e., an equal chance of crosslinking for every reactive site. A new technique is developed so that the assumption is satisfied and the sol-gel analysis can be carried out even with black-filled compounds. This technique is applied for numbers of compounds, with the same formulation but mixed under various conditions. A NR and an SBR formulations are used here. The results clearly indicate that chain scission takes place during mixing of both NR and SBR compounds.

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Gelir, Ali, Demet Kaya Aktaş, Ioan Cianga, Luminita Cianga, Yusuf Yağcı, and Yaşar Yılmaz. "Studying the sol–gel transition of styrene–divinyl benzene crosslinking co-polymerization via excimer forming dye molecules." Polymer 47, no. 16 (July 2006): 5843–51. http://dx.doi.org/10.1016/j.polymer.2006.06.017.

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35

Hada, M., M. Kaminski, P. Bockenstedt, and J. McDonagh. "Covalent crosslinking of von Willebrand factor to fibrin." Blood 68, no. 1 (July 1, 1986): 95–101. http://dx.doi.org/10.1182/blood.v68.1.95.95.

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Abstract Factor XIIIa crosslinks a limited number of substrates via epsilon(gamma-glutamyl)-lysyl bond formation. It crosslinks fibrin to itself, alpha 2-plasmin inhibitor and fibronectin to fibrin, and fibronectin to collagen. Results presented here show that plasma von Willebrand factor (vWF) is a substrate for factor XIIIa and can be crosslinked to fibrin during gel formation. vWF-fibrin crosslinking was studied in purified systems and in plasma with 125I-vWF and 131I- fibrinogen. vWF incorporation into fibrin increased with time or increasing factor XIIIa. After electrophoresis of dissolved clots, distribution of 125I and 131I was measured and showed that vWF was crosslinked to the alpha chain of fibrin and entered the high-mol-wt alpha polymer. vWF-fibrin crosslinking decreased the initial rate of alpha polymer formation. Crosslinking of vWF polymer to itself could not be demonstrated under physiologic conditions but occurred if vWF was reduced first. Factor XIIIa catalyzed incorporation of putrescine into both monomeric and polymeric vWF. Altogether, these studies indicate that factor XIIIa can readily form covalent bonds between glutamine in vWF and lysine in fibrin alpha chains. This reaction occurs readily in vitro when plasma clotting is slow and may occur in vivo under similar conditions.

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Hada, M., M. Kaminski, P. Bockenstedt, and J. McDonagh. "Covalent crosslinking of von Willebrand factor to fibrin." Blood 68, no. 1 (July 1, 1986): 95–101. http://dx.doi.org/10.1182/blood.v68.1.95.bloodjournal68195.

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Factor XIIIa crosslinks a limited number of substrates via epsilon(gamma-glutamyl)-lysyl bond formation. It crosslinks fibrin to itself, alpha 2-plasmin inhibitor and fibronectin to fibrin, and fibronectin to collagen. Results presented here show that plasma von Willebrand factor (vWF) is a substrate for factor XIIIa and can be crosslinked to fibrin during gel formation. vWF-fibrin crosslinking was studied in purified systems and in plasma with 125I-vWF and 131I- fibrinogen. vWF incorporation into fibrin increased with time or increasing factor XIIIa. After electrophoresis of dissolved clots, distribution of 125I and 131I was measured and showed that vWF was crosslinked to the alpha chain of fibrin and entered the high-mol-wt alpha polymer. vWF-fibrin crosslinking decreased the initial rate of alpha polymer formation. Crosslinking of vWF polymer to itself could not be demonstrated under physiologic conditions but occurred if vWF was reduced first. Factor XIIIa catalyzed incorporation of putrescine into both monomeric and polymeric vWF. Altogether, these studies indicate that factor XIIIa can readily form covalent bonds between glutamine in vWF and lysine in fibrin alpha chains. This reaction occurs readily in vitro when plasma clotting is slow and may occur in vivo under similar conditions.

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Chen, Minjun, Guido Bolognesi, and Goran T. Vladisavljević. "Crosslinking Strategies for the Microfluidic Production of Microgels." Molecules 26, no. 12 (June 20, 2021): 3752. http://dx.doi.org/10.3390/molecules26123752.

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This article provides a systematic review of the crosslinking strategies used to produce microgel particles in microfluidic chips. Various ionic crosslinking methods for the gelation of charged polymers are discussed, including external gelation via crosslinkers dissolved or dispersed in the oil phase; internal gelation methods using crosslinkers added to the dispersed phase in their non-active forms, such as chelating agents, photo-acid generators, sparingly soluble or slowly hydrolyzing compounds, and methods involving competitive ligand exchange; rapid mixing of polymer and crosslinking streams; and merging polymer and crosslinker droplets. Covalent crosslinking methods using enzymatic oxidation of modified biopolymers, photo-polymerization of crosslinkable monomers or polymers, and thiol-ene “click” reactions are also discussed, as well as methods based on the sol−gel transitions of stimuli responsive polymers triggered by pH or temperature change. In addition to homogeneous microgel particles, the production of structurally heterogeneous particles such as composite hydrogel particles entrapping droplet interface bilayers, core−shell particles, organoids, and Janus particles are also discussed. Microfluidics offers the ability to precisely tune the chemical composition, size, shape, surface morphology, and internal structure of microgels by bringing multiple fluid streams in contact in a highly controlled fashion using versatile channel geometries and flow configurations, and allowing for controlled crosslinking.

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Rémy, Jean-Jacques, Jean Salamero, and Jeannine Charreire. "Properties of thyrotropin receptor on cloned hybrid human thyroid cells." Acta Endocrinologica 116, no. 1_Suppl (August 1987): S186—S192. http://dx.doi.org/10.1530/acta.0.114s186.

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Abstract. Purification of the thyrotropin (TSH) binding sites from cloned human thyroid cells (GEJ) was performed after biosynthetic labelling of the cells, affinity chromatography on a human TSH-sepharose column and polyacrylamide gel electrophoresis in sodium dodecyl sulphate (PAGE-SDS). The relative molecular mass (Mr) of the GEJ cell TSH receptor (TSH-R) was approximately 48 000. This was confirmed by crosslinking [125I]TSH to GEJ binding sites with two homo-bifunctional agents: dimethyl suberimidate and disuccinimidyl suberate. Moreover, the absence of a dithiothreitol effect demonstrated that the TSH binding site on GEJ cells is formed by a single chain lacking disulphide bonds.

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Mushiake, Atsushi, Kazuyoshi Kanamori, and Kazuki Nakanishi. "Evolution of Mesopores in Monolithic Macroporous Ethylene-Bridged Polysilsesquioxane Gels Incorporated with Nonionic Surfactant." International Journal of Polymer Science 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/460835.

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By combining the micellar templating in nanometer scale with the polymerization-induced phase separation in micrometer scale, ethylene-bridged polysilsesquioxane gels with hierarchical macropores and mesopores are prepared. The difference of mesopore structures depending on the method of the solvent removal has been observed by the X-ray diffraction and the nitrogen adsorption-desorption measurements. During the hydrothermal treatment under the basic condition, the reorganization of the polysilsesquioxane gel network occurred differently depending on the alkoxy group contained in the precursors. From29Si CP/MAS NMR measurements, it was revealed that the crosslinking density of the hydrothermally treated gels was increased so that the highly ordered mesostructure of the wet gel could be preserved even after the evaporative drying of solvent.

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40

Wang, Gang, Honghai Fan, Guancheng Jiang, Wanjun Li, Yu Ye, Jitong Liu, Xiangji Kong, Zhao Zhong, and Feng Qian. "Rheology and fluid loss of a polyacrylamide-based micro-gel particles in a water-based drilling fluid." Materials Express 10, no. 5 (May 1, 2020): 657–62. http://dx.doi.org/10.1166/mex.2020.1687.

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In this paper, the cross-linked micro-gel polymer between acrylamide (AM) and N, N-Methylenebisacrylamide (MBA) was synthesized by dispersion polymerization. The initiator and crosslinking agent concentration were used to control the particle size of micro-gel polymer. The filtration property and mechanism of micro-gel were investigated comprehensively. The characteristics of micro-gel were checked by means of Fourier transform infrared spectroscopy, thermogravimetry, transmission electron microscopy, and particle size distribution, respectively. The results indicated that the cross-linked micro-gel polymer exhibited several outstanding merits, such as thermal stability (up to 200 °C), filtration control and rheological property. Microstructure analysis and particle size distribution examinations showed that the scale of micro-gel polymer was micro, which is in accord with design. Rheological tests demonstrated that the nonlinear structure of micro-gel polymer showed less impact on the apparent viscosity. The anti-high temperature property of micro-gel polymer was better than poly anioniccellulose (PAC) and asphalt widely applied in drilling fluid for anti-high temperature fluid-loss additive. As a result, the cross-linked micro-gel polymer had great potential to be applied in high temperature water-based mud.

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Xiao, Na, Yi-Tong Tang, Zhi-Shan Li, Rui Cao, Rong Wang, Jiu-Ming Zou, and Jiao Pei. "Performance of probe polymerization-conjunction-agarose gel electrophoresis in the rapid detection of KRAS gene mutation." Genetics and Molecular Biology 41, no. 3 (July 16, 2018): 555–61. http://dx.doi.org/10.1590/1678-4685-gmb-2017-0197.

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Ranjha, Nazar Mohammad, Muhammad Hanif, Zunaira Afzal, and Ghulam Abbas. "Diffusion coefficient, porosity measurement, dynamic and equilibrium swelling studies of Acrylic acid/Polyvinyl alcohol (AA/PVA) hydrogels." Pakistan Journal of Pharmaceutical Research 1, no. 2 (June 1, 2015): 48. http://dx.doi.org/10.22200/pjpr.2015248-57.

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Objective of the present work was to synthesize hydrogels of acrylic acid/polyvinyl alcohol (AA/PVA) by free radical polymerization by using glutaradehyde (GA) as crosslinkers. The hydrogels were evaluated for swelling, diffusion coefficient and network parameters like the average molecular weight between crosslink’s, polymer volume fraction in swollen state, number of repeating units between crosslinks and crosslinking density by using Flory-Huggins theory. It was found that the degree of swelling of AA/PVA hydrogels increases greatly within the pH range 5-7. The gel fraction and porosity increased by increasing the concentration of AA or PVA. Increase in degree of crosslinking, decreased the porosity and inverse was observed in gel fraction. Selected samples were loaded with metoprolol tartrate. Drug release was studied in USP hydrochloric acid solution of pH 1.2 and phosphate buffer solutions of pH 5.5 and 7.5. Various kinetics models like zero order, first order, Higuchi and Peppas model were used for in vitro kinetic studies. The results showed that the drug release followed concentration dependent effect (First order kinetics) with non-Fickian diffusion. FTIR and SEM used to study the structure, crystallinity, compatibility, thermal stability and morphology of prepared and drug loaded hydrogels respectively.

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Xia, Meng Ge, Sheng Liu, Yi Heng Wang, Yan Zhang, Yong Tao Wu, and Mei Fang Zhu. "Preparation and Properties of Nanocomposite Hydrogel by Photoinitiated Polymerization." Materials Science Forum 745-746 (February 2013): 499–506. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.499.

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A novel hybrid hydrogel (SAT gel) based on covalent crosslinking was prepared by photoinitiated polymerization. Photoactive polystyrene (PS) nanoparticles were successfully synthesized by grafting photoinitiator 2-[p-(2-hydroxy-2-methylpropiophenone)] ethylene glycol methacrylate (HMEM) onto the surface of PS nanoparticles, and characterized by nuclear magnetic resonance (NMR), fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscope (HRTEM) and dynamic light scattering (DLS). In the presence of monomer (AAm), PS nanoparticles acting as multifunctional cross-linking agents, and in-situ polymerization was carried out on the surface of photoactive particles. This study focused on the effect of photoactive PS nanoparticles concentration and illumination time on the morphology and swelling behavior of SAT hydrogels. It revealed that the three-dimensional structure and swelling ratio decreased with the increasing concentration of PS nanoparticles. Moreover, the pore size compressed with extending the illumination time. Embedding photoactive nanoparticles into hydrogels network to prepare novel hydrogels had advantages of controllable polymerization process and short forming time. This method provided a new way to prepare soft materials and to design the intelligent hydrogels.

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Kolarova Raskova, Z., J. Kousal, P. Stloukal, and Z. Krtous. "Hydrolysis of PLA-like Plasma Polymer Films with Varying Degree of Crosslinking." PLASMA PHYSICS AND TECHNOLOGY 3, no. 3 (February 14, 2016): 168–71. http://dx.doi.org/10.14311/ppt.2016.3.168.

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Poly-lactide acid (PLA) based biodegradable films are of interest for packaging materials or bioapplications. Plasma-assisted vacuum evaporation technique uses oligomers released during thermal decomposition of source polymer as precursors for plasma polymerization. Conventionally prepared PLA with mw = 10000 g/mol was used as a source polymer. Films were prepared at various RF (13.56 MHz) plasma powers (0-20 W) in order to vary the amount of crosslinking in the film.Swelling and hydrolysis of films were monitored in real time using spectroscopic ellipsometry. The concentration profile of products of hydrolysis was measured by liquid-chromatography (LC-MS). FTIR, XPS and SEM analyses were used for monitoring of film composition and surface characterization. Molecular weights of source polymer and of the plasma polymer were determined by gel-permeation chromatography (GPC). Possibility to prepare PLA-like plasma polymer films with controlled degradability by hydrolysis was demonstrated.

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Caglio, Silvia, Marcella Chiari, and Pier Giorgio Righetti. "Gel polymerization in detergents: Conversion efficiency of methylene bluevs. persulfate catalysis, as investigated by capillary zone electrophoresis." Electrophoresis 15, no. 1 (1994): 209–14. http://dx.doi.org/10.1002/elps.1150150135.

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46

Illner, Sabine, Olga Sahmel, Stefan Siewert, Thomas Eickner, and Niels Grabow. "Rheological analysis of hybrid hydrogels during polymerization processes." Current Directions in Biomedical Engineering 3, no. 2 (September 7, 2017): 699–702. http://dx.doi.org/10.1515/cdbme-2017-0148.

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AbstractDevelopment of new implant coatings with temperature-controlled drug release to treat infections after device implantation can be triggered by highly elastic hydrogels with adequate stability and adhesive strength in the swollen state. By using an ionic liquid (IL [ViPrIm]+[Br]−) as additive to N-isopropylacrylamide (NIPAAm) unique effects on volumetric changes and mechanical properties as well as thermoresponsive drug release of the obtained hybrid hydrogels were observed. In this context, rheological measurements allow the monitoring of gelation processes as well as chemical, mechanical, and thermal treatments and effects of additives. Hybrid hydrogels of pNIPAAm and poly (ionic liquid) (PIL) were prepared by radical emulsion polymerization with N,N′-methylenebis(acrylamide) as 3D crosslinking agent. By varying monomer, initiator and crosslinker amounts the multi-compound system during polymerization was monitored by oscillatory time sweep experiments. The time dependence of the storage modulus (G′) and the loss modulus (G″) was measured, whereby the intersection of G′ and G″ indicates the sol-gel transition. Viscoelastic behavior and complex viscosity of crosslinked and non-crosslinked hydrogels were obtained. Within material characterization rheology can be used to determine process capability and optimal working conditions. For biomedical applications complete hydrogelation inter-connecting all compounds can be received providing the possibility to process mechanically stable, swellable implant coatings or wound closures.

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Jaramillo-Soto, Gabriel, and Eduardo Vivaldo-Lima. "RAFT Copolymerization of Styrene/Divinylbenzene in Supercritical Carbon Dioxide." Australian Journal of Chemistry 65, no. 8 (2012): 1177. http://dx.doi.org/10.1071/ch12291.

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An experimental study on the kinetics of the reversible addition–fragmentation chain transfer (RAFT) dispersion copolymerization with crosslinking of styrene and divinylbenzene in supercritical carbon dioxide (scCO2) is presented. This is the first time that such a controlled polymer network synthesis is carried out in scCO2. S-Thiobenzoyl thioglycolic acid (TBTGA) and dibenzoyl peroxide were used as RAFT agent and initiator, respectively. The polymerizations were carried out in a high pressure cell with lateral sapphire windows at 80°C. The effect of RAFT agent concentration, including the case without RAFT controller, on polymerization rate, molecular weight development, gel fraction, swelling index, and particle morphology was analysed.

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Evingür, Gülşen Akin, Hakan Kaygusuz, F. Bedia Erim, and Önder Pekcan. "Gelation of PAAm-PVP composites: A fluorescence study." International Journal of Modern Physics B 28, no. 20 (June 19, 2014): 1450122. http://dx.doi.org/10.1142/s0217979214501227.

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Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N, N′-methylene bis (acrylamide) (BIS) as the crosslinker. Pyranine doped PAAm-poly (N-vinyl pyrrolidone) (PVP) composite were prepared with different amounts of PVP varying in the range between 0.0015 and 0.1 gr. It was observed that pyranine molecules as a fluoroprobe bind to AAm and PVP chains upon the initiation of the polymerization, causing the fluorescence spectra of the bonded pyranines shift to the shorter wavelengths. The sol–gel phase transition and its universality were monitored and tested as a function of PVP contents. Observations around the critical point show that the gel fraction exponent, β, agreed with the percolation result for below 0.025 gr PVP contents. However, classical result was observed above 0.0125 gr PVP content.

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Glusac, Jovana, Sivan Isaschar-Ovdat, Ayelet Fishman, and Biljana Kukavica. "Partial characterization of bean and maize root peroxidases and their ability to crosslink potato protein." Archives of Biological Sciences 71, no. 2 (2019): 293–303. http://dx.doi.org/10.2298/abs181016011g.

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Two fractions of Class III peroxidases (POX; EC 1.11.1.7), soluble and ionically bound to the cell wall, were partially purified from bean and maize roots and characterized. According to the measured Km, both the soluble and ionically bound to the cell wall fractions of POX had high affinity for H2O2 and the high specificity for caffeic acid. Approximate molecular weights of POX in their tertiary (native) structure were determined by modified sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE). Proteomic analysis resolved the identity and pI of different enzyme bands. The ability of maize and bean soluble peroxidase to crosslink native potato proteins was evaluated. The results obtained by SDSPAGE showed that both POX enzymes were capable of crosslinking potato protein, in particular patatin, a globular protein, with and without the presence of H2O2. To investigate the possible role of phenolic compounds in facilitating crosslinking, commercial horseradish peroxidase (HRP) with/without the addition of caffeic acid was used to crosslink potato protein. Information provided here could be useful for the purification of POX from maize and bean roots and for examination of protein-protein interactions.

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Kim, Dong-Ho, Jin-Hee Kim, Ji-Hyun Seo, Ju-Woon Lee, Sang-Yong Lim, Ho-Joon Lee, and Myung-Woo Byun. "Polymerization of SDS–PAGE gel by gamma irradiation and its use for characterization by electrophoresis of a protein." Radiation Physics and Chemistry 74, no. 5 (December 2005): 395–98. http://dx.doi.org/10.1016/j.radphyschem.2005.03.010.

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Journal articles on the topic 'Crosslinking (Polymerization) Gel electrophoresis'

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