Improved antibody adsorption performance of phenyl-based mixed-mode adsorbents by adjusting the functional group of ligand

Abstract The present work is aimed to improve the antibody adsorption performance of phenyl-based mixed-mode adsorbents by adjusting the functional group of ligand. Two new mixed-mode adsorbents coupled with 4-(aminomethyl)phenol (AMP) and 4-(aminomethyl)benzonic acid (AMA) were designed based on the structure of benzylamine (BA), where a hydroxyl or carboxyl group was introduced. Bovine serum Immunoglobulin G (IgG) and bovine serum albumin (BSA) were used as the model proteins. The adsorption isotherms of IgG and BSA were investigated at different pH values ranging from 4.0–8.9 to evaluate the adsorption performance, and protein-ligand molecular interactions were explored through addition of sodium chloride and glycerol. The results showed that both of adsorbents coupled with AMP or AMA had lower saturated binding capacities (Qm) towards BSA and higher adsorption capacity ratio of IgG to BSA when compared to BA-based adsorbents. The contributions of electrostatic interactions and hydrophobic interactions to proteins binding were different among these phenyl-based mixed mode adsorbents. Finally, AMP-based adsorbent possessing high adsorption capacity ratio of IgG to BSA and salt tolerance was selected to separate IgG from mimetic serum with purity higher than 96 %. The results indicated adjusting the functional groups of ligand to regulate the electrostatic and hydrophobic interactions of protein-ligand was useful to improve the antibody separation performance of mixed-mode adsorbents.