Hyperbranched Polyethyleneimine as a Building Block of the Surface Grafting Layer of a <scp>HCIC</scp> Cellulose Membrane Adsorber for <scp>IgG</scp> Separation

ABSTRACT Hydrophobic charge‐induced chromatography (HCIC) membrane adsorbers are cost‐effective for IgG separation but have limited adsorption capacity. Hyperbranched polyethyleneimine (HPEI) is a kind of spherical macromolecule with a high proportion of reactive amine groups, which can form an expanded three‐dimensional adsorption space upon immobilizing ligands. In this study, HPEI was used as a building block of the surface functional layer of regenerated cellulose (RC) membrane for HCIC applications. The RC membrane was reacted with epichlorohydrin and then with two HPEIs (M w = 600 and 10,000). Upon bonding 1H‐benzimidazole‐2‐carboxylic acid via the amidation reaction, the RC‐BI 600 and RC‐BI 10000 membrane adsorbers were obtained. Compared with the RC‐BI 10000 membrane, the RC‐BI 600 membrane adsorber showed a relatively higher amount of immunoglobulin G (IgG) adsorption due to better surface wettability and space utilization. After optimization, the RC‐BI 600 membrane adsorber had a static adsorption capacity of 60.3 mg/g for IgG and an ideal IgG to bovine serum albumin (BSA) separation factor of 18.1 at pH = 7. At pH = 4, the recovery of IgG reached 94%, and the activity was well retained.