Adsorption of BSA onto radiation-crosslinked poly (AAm/HPMA/MA) terpolymers (original) (raw)
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Adsorption of Bovine Serum Albumin onto Radiation-crosslinked Poly(acrylamide/acrylic acid)
Adsorption Science & Technology, 2004
Poly(acrylamide/acrylic acid) (AAm/AAc) hydrogels were prepared at initial acrylic acid compositions of 70, 80 and 85 mol%, respectively. Mixtures of AAm and AAc monomers were irradiated in a 60 Co γ-ray source at a dosage of 8 kGy. These hydrogels were used in experiments associated with the swelling, diffusion and adsorption of bovine serum albumin (BSA) from aqueous solution. The data obtained allowed the swelling and diffusion parameters for the hydrogels to be calculated. In the BSA adsorption experiments, the adsorption kinetics together with the influence of the pH of the medium, the initial BSA concentration and the composition of the hydrogels on the adsorption efficiency of the AAm/AAc hydrogels were all studied.
Adsorption of BSA on QAE-dextran: Equilibria
Biotechnology and Bioengineering, 1993
Equilibrium isotherms for adsorption of bovine serum albumin (BSA) on a strong-base (QAE) dextran-type ion exchanger have been determined experimentally. They were not affected by the initial concentration of BSA but were affected by pH considerably. They were correlated by the Langmuir equation when pH L 5.05 and by the Freundlich equation at pH 48, which is close to pl = 4 8 of BSA. The contribution of ion exchange to adsorption of BSA on the ion exchanger was determined experimentally. The maximum amounts of inorganic anion exchanged for BSA were 1% and 0.4% of the exchange capacity of the ion exchanger at pH 6.9 and 48, respectively. Since the effect of the ion exchange on the adsorption appeared small, BSA may be adsorbed mainly by electrostatic attraction when pH 2 5.05 and by hydrophobic interaction or hydrogen bonding at pH 48. When NaCl coexisted in the solution, the shape of the isotherm was similar to the Langmuir isotherm, but it is shifted to the right. When the concentration of NaCl was 0.2 mol/dm3, BSA was not adsorbed on the resin. When BSA was dissolved in pure water, the saturation capacity of BSA on HP04'-form resin was about 2 times larger than that for adsorption from the solution with buffer (pH 6.9 and 8.79). The saturation capacity for adsorption of BSA in pure water on HPOt-+ HpP04-form resin was much smaller than that from the solution with buffer. The isotherms for univalent CI-and H2P04-form resin was peculiar; that is, the amount of BSA adsorbed decreased with increasing the liquid-phase equilibrium concentration of BSA.
Adsorption of BSA on strongly basic chitosan: Equilibria
Biotechnology and Bioengineering, 1994
Equilibrium isotherms for adsorption of bovine serum albumin (BSA) on a new adsorbent, a strongly basic crosslinked chitosan (Chitopearl 2503), which is hard and is not compressed by pressure in a column, have been presented and compared with diethylaminoethyl (DEAE) Sepharose Fast Flow (hard gel). In Chitopearl 2503, when only buffer existed in the BSA solution, the isotherm was not affected by the initial concentration of BSA but it was affected by pH considerably. The isotherm was favorable when pH 2 pl (~4. 8). When NaCl existed in the BSA solution, the amount of BSA adsorbed on the resin decreased with increasing concentration of NaCI. When the concentration of NaCl was 200 mol/m3, the resin did not adsorb BSA at all. The equilibrium data were correlated by the Langmuir equation reasonably well. The BSA may be adsorbed mainly by electrostatic attraction between negatively charged BSA and positively charged quaternary ammonium groups at pH > pl and by protonation reaction of the primary ammonium groups by weak acid groups of BSA at pH = pl. These are confirmed by measuring the amount of inorganic ion exchanged for BSA. In DEAE Sepharose Fast Flow, the isotherm was favorable when pH > pl but unfavorable at pH = pl. The saturation capacity of BSA on Chitopearl 2503 is about 1.3 to 2.2 times larger than that on DEAE Sepharose Fast Flow.
Adsorption of bovine serum albumin (BSA) on polystyrene (PS) and its acid copolymer
Current Applied Physics, 2012
The effect of surface polarity on the adsorption of bovine serum albumin (BSA) on polystyrene (PS), 7% polystyrene-co-maleic anhydride (7%PSMAn) and 50% polystyrene-co-maleic acid (50%PSMA), at pH 7.4, was investigated. Polystyrene represented the non-polar surface while 7%PSMAn and 50%PSMA represented a low and high acid content copolymer. The amount of the adsorbed BSA depended on the amount of the acid content in the copolymer. BSA formed a monolayer with a side-on orientation on the low polarity PS surface, a mixed side-on and end-on orientation on 7%PSMAn and a predominantly sideon orientation on 50%PSMA. The thickness of adsorbed BSA, measured with an atomic force microscope (AFM), varied from 3 nm to 5 nm for the side-on orientation and from 10 nm to 15 nm for the end-on orientation. The average area occupied per BSA molecule was consistent with the proposed orientation, and was 34.8 nm 2 , 27.8 nm 2 and 18.0 nm 2 for PS, 7%PSMAn and 50%PSMA, respectively. The adsorption showed a concentration dependency following the Freundlich isotherm, which indicated the interactions among adsorbed BSA molecules on the polymer surface. The adsorption took place as an island-like morphology and started to fuse into a patch-like morphology at higher concentrations before achieving a complete monolayer formation. A non-uniform surface coverage and defects were observed in all cases. It is recommended that for an effective blocking of PS, 7%PSMAn and 50%PSMA, the BSA concentration should be higher than 3 mg/mL.
BSA Adsorption and Immobilization onto Charged Monodisperse Polymer Nanoparticles
Journal of Biosensors & Bioelectronics, 2015
Controlling the behavior of adsorbed and immobilized proteins is essential for protein purification and a wide range of applications, including biosensors, biocatalysis and biomedical devices. In this study, monodisperse polymer particles were synthesized by soap free emulsion polymerization and the surface functional groups were directly introduced as a monomer or chemically modified with epoxy groups to enable protein immobilization through covalent bonding. Three kinds of surface charged particles having cationic, anionic, or both, groups were synthesized and characterized. Bovine serum albumin (BSA) was selected as a model protein to study the effect of pH of a buffer solution containing protein on the adsorption and immobilization amount. Protein adsorption was found to be strongly affected by pH and matching of the global protein and polymer particle charges, respectively. When pH was below the pI of either protein (pH 3.8), negatively charged polymer particles were found to adsorb a high amount of proteins. At maximum surface coverage of BSA on negatively charged polymer particles at pH 3.8 and after subsequent rinsing of the BSA-polymer particle complex with phosphate buffer (pH 7), ~50% of BSA was desorbed. Therefore, 50% of BSA was adsorbed by ionic interaction and the remaining fraction was immobilized covalently at pH 3.8. The remaining immobilized fraction was sufficient to completely shield the anionic charge of the polymer particles. Fluorescence spectroscopy suggests that at maximum immobilized amounts, the conformation of immobilized BSA appears to be the same as in aqueous solution.
Adsorption of BSA on cross-linked chitosan: The equilibrium isotherm
The Chemical Engineering Journal, 1989
In order to make the large-scale chromatographw separation of protems more economical the authors have considered the possablhty of u2&GVg tt raew &VZ%FL&e?2& u LYZX!V-3~~~&~ ,&&-an (Chltopearl 3510) Equdbrmm wotherms of bovzn serum albumm (BSA) have been o b tamed When no inorganic elec troty tes except for a buffer coexwted m the solution, the isotherm was affected by pH considerably. When NaCl coexwted m the solutron, the wotherm was httle affected not only by the CcOYHX?YS~~th~DYX Df !I$&\ bU% DbD bY th?_DH Df the solutzon BSA can be recovered from sco>~%~orzs-;uzth h@n concenm1>ons D> fsnc) such as 1 mol drnm3 The equdzbrzum data ulere correlated by the Langnaua equatron ezm> altin Iw ~FKX.&E-Z,V &&,*u&&~ ti~*i 222 the solutwn, m whach case the selectunty was higher and the saturated capacity larger.
Surface and Interface Analysis, 2002
The understanding of protein interaction with metal surfaces has become a key question for the use of materials in medicine, in the food industry or in marine environment in connection with the process of biofouling. However, the role of the various salts present in natural seawater has never been systematically investigated. In the present work, we studied the adsorption of a protein, bovine serum albumin (BSA), on stainless-steel surfaces in artificial seawater and in aqueous solutions containing NaCl, NaCl + CaCl 2 and NaCl + MgCl 2 , the total concentration of salts being identical to that of the natural seawater (36 g l −1 ); the BSA concentration was fixed at 20 mg l −1 . After rinsing and drying, the surface was analysed by Fourier transform infrared reflection-adsorption spectroscopy (FT-IRRAS) and x-ray photoelectron spectroscopy (XPS). After immersion in aqueous solutions containing NaCl or NaCl + CaCl 2 and rinsing in saline solutions, the amount of adsorbed BSA is small. It increases by almost one order of magnitude if the immersion is performed in NaCl + MgCl 2 aqueous solution; after 24 h of immersion it reaches a saturation value very close to that attained in natural seawater. At saturation of the stainless-steel surface by the protein, the XPS metal signals were still detected, suggesting that the protein layer is heterogeneous, leaving patches of the surface almost uncovered. The amount of adsorbed BSA is reduced by almost one order of magnitude when the samples are rinsed in pure, demineralized water due to the dissolution of Mg 2+ cations and the elimination of loosely adsorbed proteins. The presence of Mg 2+ cations within the BSA layer is confirmed by angle-resolved XPS analyses.
Adsorption of BSA (Bovine Serum Albuminum) and lysozyme on poly(vinyl acetate) particles
Polímeros, 2016
Poly(vinyl acetate) (PVAc) particles find many uses in the biomedical field, including the use as particle embolizers. Particularly, embolizing particles can combine physical and chemical effects when they are doped with pharmaceuticals. For this reason, the adsorption of bovine serum albuminum (BSA) and lysozyme (used as model biomolecules) on PVAc particles produced through suspension polymerization is studied in the present manuscript in a broad range of pH values. It is shown that significant amounts of BSA and lysozyme can be adsorbed onto PVAc particles in the vicinities of the isoelectric point of the biomolecules (0.65mg of BSA and 1.0mg of lysozyme per g of PVAc), allowing for production of chemoembolizers through adsorption. Particularly, it is shown that lysozyme still presents residual activity after the adsorption process, which can constitute very important characteristic for real biomedical applications.
Journal of Chromatography A, 1996
Poly(ethylene glycol dimethacrylate-hydroxyethyl methacrylate) [poly(EGDMA-HEMA)] microbeads, in the size range 150-200 pm, were produced by a modified suspension copolymerization of EGDMA and HEMA. Congo Red was attached covalently to the poly(EGDMA-HEMA) microbeads, then Cu(II) ions were incorporated within the microbeads by chelating with the immobilized dye molecules. Different amounts of Cu(I1) ions [0.5-2.9 mg Cu(II)/g polymer] were conjugated on the microbeads by changing the initial concentration of Cu(I1) ions, pH and ionic strength. Bovine serum albumin (BSA) adsorption on these microbeads from aqueous solutions containing different amounts of BSA at different pH and ionic strengths was investigated in batch reactors. The non-specific BSA adsorption on the poly(EGDMA-HEMA) microbeads was almost zero. Congo Red derivatization significantly increased the BSA adsorption (up to 90 mg BSA/g polymer). A further increase in the adsorption capacity (up to 136 mg BSA/g polymer) was observed when Cu(I1) ions were incorporated. More than 90% of the adsorbed BSA was desorbed in 1 h in a desorption medium containing 0.5 M NaSCN at pH 8.0.