Home About us Contact
|
Home About us Contact | ||
|
|
||
Macroporous Poly (macroporou + poly)
Selected AbstractsOn-line concentration of peptides and proteins with the hyphenation of polymer monolithic immobilized metal affinity chromatography and capillary electrophoresisELECTROPHORESIS, Issue 11 2005Lingyi Zhang Abstract An iminodiacetic acid (IDA)-type adsorbent is prepared at the one end of a capillary by covalently bonding IDA to the monolithic rods of macroporous poly(glycidyl methacrylate,co -ethylene dimethacrylate). Cu(II) is later introduced to the support via the interaction with IDA. By this means, polymer monolithic immobilized metal affinity chromatography (IMAC) materials are prepared. With such a column, IMAC for on-line concentration and capillary electrophoresis (CE) for the subsequent analysis are hyphenated for the analysis of peptides and proteins. The reproducibility of such a column has been proved good with relative standard deviations (RSDs) of dead time of less than 5% for injection-to-injection and 12% for column-to-column (n = 3). Through application on the analysis of standard peptides and real protein samples, such a technique has shown promising in proteome study. [source] Preparation of normal-phase HPLC stationary phase based on monodisperse hydrophilic polymeric beads and their applicationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Bolin Gong Abstract The monodisperse, 5.0 ,m hydrophilic macroporous poly(glycidymethacrylate- co -ethylenedimethacrylate) beads were first prepared based on monosized linear poly(glycidylmethacrylate) beads as seed by using a single-step swelling and polymerization method. The seed beads prepared by dispersion polymerization exhibited good absorption of the monomer phase. The pore size distribution of the beads was evaluated by mercury instrusion method. The surface area was calculated from the BET isotherms of nitrogen adsorption and desorption. The beads were modified to be a normal-phase liquid chromatographic (NPLC) stationary phase for high performance liquid chromatography (HPLC) in the following steps. First, the beads were completely hydrolyzed. Second, hydrolyzed particles were reacted with epichlorihydrin followed by another hydrolysis of the newly introduced epoxide groups. The retention properties of the NPLC stationary phase were easily modulated by changes in the composition of the mobile phase. The performance of theses beads was demonstrated with the separation of a variety of polar compounds. The satisfactory results were obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Fabrication and surface modification of macroporous poly(L -lactic acid) and poly(L -lactic- co -glycolic acid) (70/30) cell scaffolds for human skin fibroblast cell cultureJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 3 2002Jian Yang Abstract The fabrication and surface modification of a porous cell scaffold are very important in tissue engineering. Of most concern are high-density cell seeding, nutrient and oxygen supply, and cell affinity. In the present study, poly(L -lactic acid) and poly(L -lactic- co -glycolic acid) (70/30) cell scaffolds with different pore structures were fabricated. An improved method based on Archimedes' Principle for measuring the porosity of scaffolds, using a density bottle, was developed. Anhydrous ammonia plasma treatment was used to modify surface properties to improve the cell affinity of the scaffolds. The results show that hydrophilicity and surface energy were improved. The polar N-containing groups and positive charged groups also were incorporated into the sample surface. A low-temperature treatment was used to maintain the plasma-modified surface properties effectively. It would do help to the further application of plasma treatment technique. Cell culture results showed that pores smaller than 160 ,m are suitable for human skin fibroblast cell growth. Cell seeding efficiency was maintained at above 99%, which is better than the efficiency achieved with the common method of prewetting by ethanol. The plasma-treatment method also helped to resolve the problem of cell loss during cell seeding, and the negative effects of the ethanol trace on cell culture were avoided. The results suggest that anhydrous ammonia plasma treatment enhances the cell affinity of porous scaffolds. Mass transport issues also have been considered. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 438,446, 2002 [source] Preparation of macroporous poly(N -isopropylacrylamide) hydrogel with improved temperature sensitivityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2003J.-T. Zhang Macroporous poly(N -isopropylacrylamide) (PNIPA) hydrogels with improved temperature sensitivity were prepared in aqueous glucose solutions. Compared with the conventional PNIPA hydrogel prepared in water, the gels thus prepared showed significantly faster response as the temperature increased above the lower critical solution temperature. The improved properties were due to the macroporous structure, that was formed during gel preparation caused by the phase separation in glucose solutions. [source] Poly[(vinylidene fluoride)- co -trifluoroethylene] Membranes Obtained by Isothermal Crystallization from SolutionMACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2010Armando Ferreira Abstract Electroactive macroporous poly[(vinylidene fluoride)- co -trifluoroethylene] membranes have been produced by solvent evaporation at room temperature, starting with a diluted solution of the copolymer in dimethylformamide. The pore architecture consists of interconnected spherical pores. This architecture is independent of the membrane thickness. The thickness of the membranes ranges from a few to several hundred µm, using spin coating and evaporation in static conditions, respectively. The pore structure is explained by a spinodal decomposition of the liquid/liquid phase separation and crystallization in the copolymer-rich phase. [source] Enhancing the cell affinity of macroporous poly(L -lactide) cell scaffold by a convenient surface modification methodPOLYMER INTERNATIONAL, Issue 12 2003Jian Yang Abstract In this study, the macroporous poly(L -lactide) (PLLA) cell scaffold was modified for enhancing its cell affinity by an improved surface-treating medium, a mixture of aqueous 0.25 M NaOH/ethanol. Ethanol was applied as a co-treating medium to wet the polylactone and assist the hydroxide nucleophilic attack on the ester bond. Low concentration of NaOH could be applied, severe bulk degradation could be avoided and the residual alkali was easy to remove. Treating time could also be shortened. After treatment under optimal conditions, the surface hydrophilicity and surface energy of PLLA were improved significantly and the surface roughness was also changed. Modification of the spherulite structure on PLLA surface was observed with the treating time using a computer-assisted image analysis system (CAIAS). The results of gel permeation chromatography measurements indicated that only the outer layer of the PLLA was modified and the bulk properties were not altered. Mouse 3T3 fibroblasts culture results indicated that the improved surface-treating medium was effective and convenient for enhancing the cell affinity of PLLA cell scaffold. Copyright © 2003 Society of Chemical Industry [source] High-performance affinity chromatography with immobilization of protein A and L-histidine on molded monolithBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2002Quanzhou Luo Abstract Reactive monoliths of macroporous poly(glycidyl methacrylate- co -ethylene dimethacrylate) have been prepared by "in-situ" copolymerization of the monomers in the presence of porogenic diluents. Protein A and L-histidine were immobilized on the monoliths directly or through a spacer arm, respectively. The properties of these two kinds of affinity columns were characterized, and the results showed that the columns with coupling of ligands by a spacer arm have some extent of non-specific adsorption for bovine serum albumin. The affinity column based on the monolithic polymer support provided us with good hydrodynamic characteristic, low flow resistance, and easy preparation. These two affinity columns were used for the purification of immunoglobulin G from human serum. The purity of the purified IgG was detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The stability of the protein A affinity column was investigated, and its performance remained invariable after half a year. The effects of the nature and the pH of the buffer system on the adsorption capacity of human IgG on histidyl affinity column were also investigated. The protein A affinity column is favorable for rapid analysis of human IgG samples. In contrast, the advantages of mild elution conditions, high stability, as well as low cost provide the histidyl column further potential possibility for fast removal of IgG from human plasma in clinical applications. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 481,489, 2002. [source] Synthesis of the hydrophobic,hydrophilic macroporous poly divinylbenzene/poly(sodium acrylate) IPN resin and adsorption performance for berberinePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Guqing Xiao Abstract The macroporous polydivinylbenzene/poly(methyl acrylate) interpenetrating polymer network (PDVB/PMA IPN) was prepared by the sequential suspension polymerization method, and was modified to be hydrophobic,hydrophilic macroporous polydivinylbenzene/poly (sodium acrylate) IPN (PDVB/PNaA IPN) by converting the PMA to PNaA under the condition of base. The effects of different mass ratio of the two networks and different cross-linking degree of the second network on the pore structure and adsorption capacity of PDVB/PNaA IPN resin were studied. The PDVB/PNaA IPN resin whose adsorption quantity is the biggest was chosen to study further. The pore structure, the weak acid exchange capacity, the water retention capacity, and the swelling ability of PDVB/PNaA IPN resin were measured. The study focused on the adsorption isotherms of berberine at different temperatures. Isosteric adsorption enthalpy, adsorption Gibbs free energies can be calculated according to thermodynamic functions. The results show that the saturated adsorption quantity of berberine is up to 109.4,mg,ml,1 (wet resin) by the way of dynamic adsorption and desorption experiment. The resin could be reused by the mixture with 0.5% sodium chloride and 80% ethanol. On the one hand the hydrophobic PDVB in the PDVB/PNaA IPN resin has the ability of adsorption using ,,, interaction, and on the other hand the hydrophilic PNaA in the PDVB/PNaA IPN resin has the ability of adsorption using ion exchange interaction. An important conclusion can be drawn that the PDVB/PNaA IPN resin has a promising application prospect in extracting and separating quaternary ammonium type alkaloids such as berberine. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||