Adsorption Capacity Of Bovine Serum Albumin Research Articles

Preparation and performance of cellulose acetate/polyethyleneimine blend microfiltration membranes and their applications

A modified microfiltration membrane has been prepared by blending a matrix polymer with a functional polymer. Cellulose acetate (CA) was blended with polyethyleneimine (PEI), which was then crosslinked by polyisocyanate, in a mixture of solvents. In the membrane, PEI can supply coupling sites for ligands in affinity separation or be used as ligands for metal chelating, removal of endotoxin or ion exchange. The effects of the time of phase inversion induced by water vapor, blended amount of PEI and amount of crosslinking agent on membrane performance were investigated. The prepared blend membranes have specific surface area of 12.04–24.11 m 2/g and pure water flux (PWF) of 10–50 ml/cm 2 min with porosity of 63–75%. The membranes, made of 0.15 50 wt.% PEI/CA ratio and 0.5 crosslinking agent/PEI ratio, were applied to adsorbing Cu 2+ and bovine serum albumin (BSA) individually. The maximum adsorption capacity of Cu 2+ ion on the blend membrane is 7.42 mg/g dry membrane. The maximum adsorption capacities of BSA on the membranes with and without chelating Cu 2+ ion are 86.6 and 43.8 mg/g dry membrane, respectively.

Ionic strength dependence of protein adsorption to dye‐ligand adsorbents

AbstractThe adsorption equilibria and kinetics of bovine serum albumin (BSA) and lysozyme to two Cibacron Blue 3GA (CB) modified agarose gels, that is, 6% agarose‐coated steel (6AS) and Sepharose CL‐6B, in 0.01 kmol·m−3 tris‐HCl buffer (pH 7.5) were studied. Effects of aqueous‐phase ionic strength on both the adsorption equilibrium and uptake rate of the proteins were significant and distinctly different between BSA and lysozyme. The adsorption of lysozyme decreased monotonically with increasing ionic strength. Ionic strengths, however, maximized BSA adsorption capacities of the two CB‐modified agarose gels in the tris‐HCl buffer (about 0.2 kmol·m−3 for CB‐6AS and 0.05 kmol·m−3 for CB‐Sepharose), when the pore‐size difference of the two matrixes and electrostatic interactions between the BSA and CB molecules of like charge were considered. The effective diffusivity of BSA, derived from a pore‐diffusion model, to both the CB‐modified agarose gels increased significantly with the increasing ionic strength at the ionic strength range of 0.01 to 0.3 kmol·m−3, due to the electrostatic interactions between the BSA and CB molecules of like charge. In contrast, the effective diffusivities of lysozyme to CB‐Sepharose in the buffer containing 0.1 and 0.3 kmol·m−3 NaCl were nearly the same.

A new specific metal ion chelated-poly(N-vinylimidazole) gel sorbents for albumin adsorption-desorption

Poly(N-vinylimidazole) (PVIm) hydrogels were prepared by γ-irradiating binary mixtures of N-vinylimidazole-water in a 60Co-γ source having 4.5 kGy/h dose rate. These affinity gels having different swelling ratio of Cu(II)-chelated, Co(II)-chelated and plain PVIm in acetate buffer were used in the albumin adsorption studies. Bovine serum albumin (BSA) adsorption on these gels from aqueous solutions containing different amounts of BSA at different pH adjusted with acetate and phosphate buffer was investigated in batch reactors. The adsorption capacities of BSA on/in the gels were decreased dramatically by increasing the ionic strength (I) adjusting with NaCl. BSA adsorption capacities of the metal ion-chelated gels were higher than the plain PVIm gel even if the swelling ratio of the metal ion-chelated gels was very low comparing to the PVIm gel. The rigidity of the metal ion-chelated gel is very high and it can be used for the column applications. More than 95% of BSA were desorbed in 3 h in the desorption medium containing KSCN for PVIm gel and EDTA for metal ion-chelated gels. These results indicate that PVIm and metal ion-chelated PVIm gels are very efficient to remove BSA and the different metal ion-chelated PVIm gels show different affinity for BSA or biomolecules.

Monosize and non-porous p(HEMA-co-MMA) microparticles designed as dye- and metal-chelate affinity sorbents

Congo red was immobilised onto monosize and non-porous poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [p(HEMA-co-MMA)] copolymer microparticles (4.0 μm in diameter). Then Fe(III) ions were complexed by chelation with the immobilised congo red molecules. Different amounts of Fe(III) ions were loaded on the dye-derived microparticles by changing the concentration of Fe(III) ions and pH of the reaction medium. Congo red-derived and Fe(III)-complexed microparticles were used in the adsorption of glucose oxidase, catalase, lysozyme and bovine serum albumin. The maximum adsorption capacities of these microparticles were determined by changing pH and the concentration of the proteins in the adsorption medium. Their adsorption behavior can be described at least approximately with the Langmuir equation. Glucose oxidase, catalase, lysozyme and bovine serum albumin adsorption capacities of the Fe(III) complexed microparticles (165.1, 135.2, 67.6 and 44.5 mg g −1) were higher than those of the congo red-immobilised microparticles (125.9, 94.2, 35.8 and 21.2 mg g −1, respectively). The non-specific adsorption of the proteins on the p(HEMA-co-MMA) microparticles was negligible. The resulting dye- and metal-chelate affinity microparticles have excellent reusability and long term storage stability.

Dye-ligand column chromatography: Albumin adsorption from aqueous media and human plasma with dye-affinity microbeads

Cibacron Blue F3GA was covalently coupled with poly(ethylene glycoldimethacrylate-2-hydroxyethylmethacrylate) [poly(EGDMA-HEMA)] microbeads via the nucleophilic substitution reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA molecules under alkaline conditions. The affinity sorbent carrying 16.5 μmol Cibacron Blue F3GA/g polymer was then used for bovine serum albumin (BSA) adsorption from aqueous protein solutions and from human plasma in a packed-bed column. The BSA adsorption capacity of the microbeads decreased with an increase in the recirculation rate. High adsorption rates were observed at the beginning, then equilibrium was gradually achieved in about 60 min. The BSA concentration in the mobile phase was also effective on adsorption. BSA adsorption was first increased with BSA concentration, then reached a plateau that was about 57.3 mg BSA/g. Higher BSA adsorption was observed at lower ionic strength. The maximum adsorption was observed at pH 5.0, which is the isoelectric pH of BSA. Higher human serum albumin adsorption was achieved from human plasma (109.6 mg HSA/g). High desorption ratios (over 94% of the adsorbed albumin) were achieved by using 1.0M NaSCN (pH 8.0) in 30 min. It was observed that albumin could be repeatedly adsorbed and desorbed without a significant loss in adsorption capacity.

Adsorption of Bovine Serum Albumin from salt solution onto activated carbon

One of the wastewaters from tanning industry (soak liquor) contains 0.4 g/l of dissolved protein. During coagulation and flocculation 41 % of protein was removed. A suggestion has been made to remove the residual protein by adsorption technique. The optimum conditions for adsorption of Bovine Serum Albumin (BSA) on rice bran based activated carbon (RBAC) have been determined. Maximum adsorption of BSA took place at pH 7.O. Ionic strength was found to have influence on the adsorption behaviour. Adsorption capacity of BSA onto charcoal surface decreased with increase in temperature. Enthalpy of adsorption in all cases was found to be within −19 to −57 kJ/mole, indicating exothermic nature of the process. Applicability of adsorption technique to the removal of dissolved protein from soak water has been studied. The maximum removal of protein occurred at pH 7.0 and the ratio of protein removed to weight of adsorbent was 3.22×10−3 g/g.

Albumin adsorption on to large-size monodisperse polystyrene latices having functional groups on their surfaces

Adsorption of bovine serum albumin (BSA) on to large-size monodisperse latices was investigated. Polystyrene (PS) latices in two different sizes with hydroxyl, amino and carboxyl groups on their surfaces were produced by following a two-step polymerization procedure. The effects of pH and ionic strength of the medium on BSA adsorption capacity of the latices were investigated in the existence of two different anions and three different cations, Cl − and SCN − and Na + Call and Mg 2+ respectively. Maximum adsorption capacities for all latices were obtained near the isoelectric point of BSA. No BSA adsorption was observed with PS latex, especially in the alkaline pH region. The BSA adsorption capacity decreased with increasing ionic strength. Different adsorption behaviors were noted in the PS latices having functional groups on their surfaces.

PREPARATION OF CELLULOSE ION-EXCHANGE ADSORBENTS AND THEIR BOVINE SERUM ALBUMIN ADSORPTION CAPACITY

Microcrystalline cellulose powder for column chromatography was treated with N, N′-bis (2-chloroethyl) piperazine or N, N′-bis (2-hydroxyethyl) piperazine and epichlorohydrin in the presence of sodium hydroxide solution. Bovine serum albumin adsorption capacity of the products was examined and compared with that of commercially available diethylaminoethyl cellulose.