Quaternized Nanofiber-Based Anion-Exchange Chromatography Membrane with Periodic Diagonal Surface Structure for Efficient Protein Separation

Constructing a nanofibrous membrane with high flow rate surface pore structure and high-density ligand chemical structure is a promising strategy to balance the trade-off between high flow rates and high adsorption capacity for protein separation and purification. Herein, a nanofiber-based ion-exchange chromatography membrane with a periodic diagonal surface structure and high ionic strength ligands was fabricated using dispersion in situ cross-linking, wet coating, and template printing with a three-wire diagonal woven mesh. For this membrane, EVOH nanofibers were used as skeleton, glutaraldehyde (GA) as cross-linking agent, and quaternized chitosan (QCS) as binder and functional ligand. The results show that when QCS content was 35%, the morphology, pore size, and comprehensive performance of NFM-QCS were optimized. NFM-QCS demonstrated high flow rates under low pressure, a high static adsorption capacity of 1285.16 mg/g, and a high dynamic adsorption capacity of 135.63 mg/mL (1 mm/min) for bovine serum albumin (BSA), which is superior to reported state-of-the-art and commercial ion-exchange chromatography columns. Based on the excellent adsorption performance, NFM-QCS can efficiently separate and purify IgG from the mixed solution of BSA and IgG. Our work provides a facile approach for the preparation of a high-performance ion-exchange chromatography membrane for protein separation.