Ionic strength dependence of protein adsorption to dye‐ligand adsorbents

Zhang, Songping; Sun, Yan

doi:10.1002/aic.690480118

Cited by 64 publications

(32 citation statements)

References 28 publications

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“…The effective porosities of the adsorbents for g-globulin (e p ) were measured in a bath-diffusion experiment as described by Zhang and Sun [34]. Briefly, 1.0 mol/L NaCl in 50 mmol/L acetate buffer (pH 5.0) and 20 mmol/L citrate buffer (pH 4.0) were used in the determination of e p for g-globulin in cation-exchange and MMC adsorbents, respectively.…”

Section: Characteristics Of Adsorbentsmentioning

confidence: 99%

Effect of dextran layer on protein uptake to dextran‐grafted adsorbents for ion‐exchange and mixed‐mode chromatography

Shi

Sun

2011

J of Separation Science

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In the current research, a series of dextran-grafted adsorbents were prepared using sulfopropyl and 4-(1H-imidazol-1-yl) aniline as chromatographic ligands for ion-exchange (IEC) and mixed-mode chromatography (MMC) to respectively investigate the influence of dextran layer on adsorption of γ-globulin. Experimental evidences of static adsorption on dextran-grafted IEC adsorbents showed that adsorption capacity of γ-globulin increased with dextran content. It could be attributed to the multilayer adsorption of charged protein in dextran layer and thus further induced a significant electrical potential gradient at the boundary of adsorbed area and its proximity, improving mass transfer in combination with concentration gradient. In contrast to IEC adsorbents, adsorption capacity and effective diffusivity of dextran-grafted MMC adsorbents did not change obviously with dextran grafting. It was considered that hydrophobic ligands immobilized onto dextran-grafted MMC adsorbents were stuck together at pH 8.0, resulting in the collapse of dextran layer. In concert with measured effective porosity for γ-globulin at pH 4.0, it was confirmed that dextran layer in MMC adsorbent was more complicated and influenced significantly by buffer pH. It was also manifested by protein adsorption at different pHs. Thus, it revealed the complexity in intraparticle mass transfer of the protein in dextran-grafted MMC adsorbent.

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Section: Characteristics Of Adsorbentsmentioning

confidence: 99%

Effect of dextran layer on protein uptake to dextran‐grafted adsorbents for ion‐exchange and mixed‐mode chromatography

Shi

Sun

2011

J of Separation Science

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“…A volume-weighted mean particle diameter was utilized to express the mean particle size (d p ). The particle porosities were measured by the batch diffusion method (Zhang and Sun, 2002) by triplicate experiments. The total porosity was determined with acetone as the probe, while the effective porosity E p for protein was measured with BSA.…”

Section: Solid Phase Characterizationmentioning

confidence: 99%

A novel superporous agarose medium for high‐speed protein chromatography

Shi

Zhou

Sun

2005

Biotech & Bioengineering

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A novel superporous agarose (SA) bead characterized by the presence of wide pores has been fabricated by water-in-oil emulsification using solid granules of calcium carbonate as porogenic agent. After cross-linking, the solid granules were removed by dissolving them in hydrochloric acid. Then, the gel was modified with diethylaminoethyl groups to create an anion exchanger, SA-DEAE, for protein adsorption. A homogeneous agarose (HA) bead was also produced and modified with DEAE for comparison. It was found that the porosity of SA-DEAE was about 6% larger than that of HA-DEAE. Moreover, both optical micrographs and confocal laser scanning microscopy (CLSM) of the ion exchangers with adsorbed fluorescein isothiocyanate (FITC) labeled IgG revealed the superporous structure of the SA medium. In addition, the SA-DEAE column had lower backpressure than the HA-DEAE column, confirming the convective flow of mobile phase through the wide pores. Due to the presence of the wide pores, more channels were available for protein transport and, furthermore, more diffusive pores in the agarose network were accessible for the protein approach from different directions. This led to 40% higher protein capacity and two times higher effective pore diffusivity in the SA-DEAE than in HA-DEAE. Moreover, an increase of the efficiency of the SA-DEAE column until a flow rate of 5 cm/min and the independency of the column efficiency at flow rates from 5 to 17.8 cm/min was found, indicating that intraparticle mass transfer was intensified by convective flow at elevated flow rates. Therefore, the chromatographic resolution of IgG and BSA was little affected up to a flow rate of 17.8 cm/min. The results indicate that the SA medium is favorable for high-speed protein chromatography.

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“…In a small pore of about 35 nm, solute can only diffuse into the bead by the Fick's law for common IEC [18,19], so the interstitial pressure-driven flow rate does not contribute to the convection inside a bead. However, in pIEEC, the electro-kinetic phenomena could give rise to the intraparticle convection of solutes, which is periodical and depends on the EF direction.…”

Section: Control Equation In Single Beadmentioning

confidence: 99%

Protein adsorption‐dependent electro‐kinetic pore flow: Modeling of ion‐exchange electrochromatography with an oscillatory transverse electric field

et al. 2010

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Electro-kinetic acceleration of protein mass transfer was studied by dynamic chromatographic experiments and computer simulations on IEC with an oscillatory transverse electric field (EF) perpendicular to the mobile-phase flow (pIEEC). The breakthrough behavior of BSA was investigated at different electric current densities. A two-dimensional mathematical model has been established to describe the electro-kinetic convection-diffusion behavior of protein adsorption in a single adsorbent particle. The equation was coupled with the axial dispersion model to simulate the dynamic adsorption process in the pIEEC. The model parameters were determined by independent experiments or calculations. It was found that protein adsorption led to an exponential decrease of intraparticle electro-kinetic flow with increasing protein adsorption. Taking this effect into consideration, the model calculations could well describe dynamic breakthrough curves. Moreover, protein distribution in adsorbents was observed to present excursion along the periodical oscillatory EF direction. At the beginning of pIEEC, intraparticle convection caused by the EF contributed more to the enhancement of dynamic binding capacity. Finally, it was confirmed that both the EOF and electrophoresis contributed to the acceleration of mass transfer.

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Ionic strength dependence of protein adsorption to dye‐ligand adsorbents

Abstract: NaCl were nearly the same.

Cited by 64 publications

References 28 publications

Effect of dextran layer on protein uptake to dextran‐grafted adsorbents for ion‐exchange and mixed‐mode chromatography

Effect of dextran layer on protein uptake to dextran‐grafted adsorbents for ion‐exchange and mixed‐mode chromatography

A novel superporous agarose medium for high‐speed protein chromatography

Protein adsorption‐dependent electro‐kinetic pore flow: Modeling of ion‐exchange electrochromatography with an oscillatory transverse electric field

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