- Determination of substitution positions in hyaluronic acid hydrogels using NMR and MS based methods
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In hydrogels of cross-linked polysaccharides, the total amount of cross-linker and the degree of cross-linking influence the properties of the hydrogel. The substitution position of the cross-linker on the polysaccharide is another parameter that can influence hydrogel properties; hence methods for detailed structural analysis of the substitution pattern are required. NMR and LC-MS methods were developed to determine the positions and amounts of substitution of 1,4-butanediol diglycidyl ether (BDDE) on hyaluronic acid (HA), and for the first time it is shown that BDDE can react with any of the four available hydroxyl groups of the HA disaccharide repeating unit. This was achieved by studying di-, tetra-, and hexasaccharides obtained from degradation of BDDE cross-linked HA hydrogel by chondroitinase. Furthermore, amount of linker substitution at each position was shown to be dependent on the size of the oligosaccharides. For the disaccharide, substitutions were predominantly at ΔGlcA-OH2 and GlcNAc-OH6 while in the tetra- and hexasaccharides, it was mainly at the reducing end GlcNAc-OH4. In the disaccharide there was no substitution at this position. Since chondroitinase is able to completely hydrolyse non-substituted HA into unsaturated disaccharides, these results indicate that the enzyme is prevented to cleave on the non-reducing side of an oligosaccharide substituted at the reducing end GlcNAc-OH4. The procedure can be adopted for the determination of substitution positions in other types of polymers.
- Wende, Frida J.,Gohil, Suresh,Mojarradi, Hotan,Gerfaud, Thibaud,Nord, Lars I.,Karlsson, Anders,Boiteau, Jean-Guy,Kenne, Anne Helander,Sandstr?m, Corine
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- Study of imidazole performance as pseudo-affinity ligand in the purification of IgG from bovine milk
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The spherical sepharose CL-6B beads were activated by epichlorohydrin in different epoxy contents (80, 120 and 160 μmolepoxide/mLgel) and, L-histidine and imidazole as pseudo-affinity ligands were covalently immobilized to them. Some linkers with different length, (1,2-ethanediol diglycidyl ether and 1,4-butanediol diglycidyl ether) were synthesized for activation of sepharose and the activated sepharose beads modified with imidazole and the performance of these adsorbents in the purification of immunoglobulin G from bovine milk were evaluated. Among the L-histidine bearing adsorbents, higher adsorption of IgG (0.28 mg/mL) was obtained by adsorbent with the lower concentration of L-histidine. The highest amount of IgG adsorption (0.53 mg/mL) was obtained by imidazole bearing adsorbent with the highest amount of imidazole and Among the adsorbents with synthesized linkers, the adsorbent with 1,2-ethanediol diglycidyl ether showed better performance and was able to purify 0.25 mg/mL IgG with high purity. The synthesized pseudo-affinity adsorbents represented the abbility to purify immunoglobulin G in one-step process with high purity and efficiency.
- Abbasi, Hassan,Pourrostam-Ravadanaq, Pariya,Safa, Kazem D.
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- Enantiopure or enantioenriched BDDE and its use as crosslinking agent in the manufacture of cross-linked products
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Enantiomers of butanediol diglycidyl ether (BDDE) are present in an enantiomerically enriched enantioenriched mixture of BDDE stereisomers or in an enantiomerically pure BDDE. Enantiomerically enriched or pure BDDE is useful as a cross-linking agent, such as in the preparation of a cross-linked hyaluronic acid product.
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Page/Page column 4; 13
(2018/03/23)
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- Diol glycidyl ether-bridged cyclens: Preparation and their applications in gene delivery
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Polymeric 1,4,7,10-tetraazacyclododecanes (cyclens) using diol glycidyl ether with different chain length as bridges (5a-e) were designed and synthesized from various diols, 1,7-diprotected cyclen and epichlorohydrin. The molecular weights of the title polymers were measured by GPC with good polydispersity. Agarose gel retardation and fluorescent titration using ethidium bromide showed good DNA-binding ability of 5. They could retard plasmid DNA (pDNA) at an N/P ratio of 4-6 and form polyplexes with sizes around 100-250 nm from an N/P ratio of 10 to 60 and relatively low zeta-potential values (5-22 mV). The cytotoxicity of 5 assayed by MTT is much lower than that of 20 kDa PEI. In vitro transfection against A549 and 293 cells showed that the transfection efficiency (TE) of 5c/DNA polyplexes is close to that of 20 kDa PEI at an N/P ratio of 5. Structure-activity relationship (SAR) of 5 was discussed in their DNA-binding, cytotoxicity, and transfection studies. The TE of 5c/DNA polyplexes could be improved by the introduction of 50 μM of chloroquine, the endosomolytic agents, to pretreated cells. These studies may extend the application areas of macrocyclic polyamines, especially for cyclen.
- Yi, Wen-Jing,Feng, Zhi-Hua,Zhang, Qin-Fang,Zhang, Ji,Li, Ling-Dong,Zhu, Wen,Yu, Xiao-Qi
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experimental part
p. 2413 - 2421
(2011/05/14)
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- Dinuclear macrocyclic polyamine zinc(II) complexes linked with flexible spacers: Synthesis, characterization, and DNA cleavage
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Dinuclear macrocyclic polyamine zinc(II) complexes, which have two cyclen groups linked by flexible spacers, have been synthesized as DNA cleavage agents. The structures of these new dinuclear complexes are consistent with the data obtained from elemental analysis, MS and 1H NMR spectroscopy. The catalytic activity of these dinuclear complexes on DNA cleavage was studied. The results showed that the dinuclear zinc(II) complexes can catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) (Form I) under physiological conditions to produce selectively nicked DNA (Form II).
- Peng, Wei,Liu, Pei-Yan,Jiang, Ning,Lin, Hong-Hui,Zhang, Guo-Lin,Liu, Yi,Yu, Xiao-Qi
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p. 374 - 385
(2008/02/01)
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- Thiopolymers, their derivatives and methods for their preparation and use
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A method for producing products for separation, ion exchange or as basic material for the preparation of various derivatives designed for separation purposes and adsorption purposes by means of a polymer being activated with a reagent containing at least two bifunctional groups so that at least one of the reactive, functional groups in each molecule is bonded to the polymer while leaving a considerable amount of remaining groups unreacted but still reactive so that the activated polymer can be caused to react with thiosulphate after surplus reagent has been eliminated. The invention also relates to the produced products or their derivatives consisting of a water-soluble hydroxyl group or amino group containing polymer substituted with organic side-chains, each containing one or more thiosulphate groups or derivatives of such groups and the use of the products for purification of water, separation, immobilization of enzymes, etc.
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