Fabrication and characterization of an anion exchange-based monolithic column, using γ-aminobutyric acid as a ligand, contained in a 3D printed casing for separation of biomolecules

Abstract

A poly(GMA-co-EDMA) monolith was synthesized within a 3D printed housing of 4 different materials and modified with γ-aminobutyric acid, a non-protein amino acid. The monoliths were synthesized with 3 different surface pretreatments in housing with 5 mm i.d. and 20 mm length channel. The functionalization of the monolith was done by by Shiff-based method using diethylenediamine as a spacer. SEM images evidenced that a homogeneous surface monolith on γ-MAPS treated surfaces while direct synthesis had scales and big agglomerates within the polymeric matrix. Raman spectroscopy evidenced the different modifications the resin housing surfaces experienced and confirmed the presence of the ligand. On the other hand, BET analysis found surface areas ranging 7.459 m2/g to 20.147 m2/g and micropores range from 0.432 to 1.736 nm, being 4.70 nm the most common pore. The fabricated monolithic columns with EDMA-G, γ-MAPS at 20%, γ-MAPS at 30% treatments exhibited ionic capacities of 0.056±0.001, 0.174±0.001 and 0.293±0.015 mmol Cl⁻/mL, respectively. EDMA-G column exhibited the best performance for fractionating proteins from a concentrated bacterial lysate from E. coli strain BL21 star with plasmid pSB21C3, producing RFP. Eventhough the column was able to retain 20% of the total RFP, improvement needs to be done to increase the ligand density and, in consequence, the adsorption capacity.