Suppression of Hydrophobicity and Optimizations of a Ligand-Immobilization for Effective Affinity Chromatography Using a Spongy Monolith

In this study, we reveal the suppression of non-specific hydrophobic interaction in poly(ethylene-co-glycidylmethacrylate) (PEGM) based spongy monolith (SPM), PEGM-SPM, which has recently be reported as a new platform of separation medium for affinity chromatography in our previous study, by an simple acidic treatment. Additionally, the immobilization procedures of protein-A toward the PEGM-SPM and the separation conditions for immunoglobulin G (IgG) were optimized for further effective affinity separations. As a result of treatment by a mixture of trifluoroacetic acid and acetonitrile, the hydrophobicity was dramatically suppressed in the PEGM-SPM. The optimizations for the density of PEGM in the PEGM-SPM, the protein A immobilization, and the binding/releasing conditions showed that variety of proteins and peptides were not retained on the protein A immobilized spongy column at all while IgG was absolutely separated by a simple stepwise pH gradient condition.