High-affinity sulfonated materials with transition metal counterions for enhanced protein separation in dual-layer hollow fiber membrane chromatography

High-affinity membrane materials have been successfully synthesized through a combination of the polymer sulfonation reaction with transition metal counterion exchange treatment. This type of promising materials were embodied for the first time with the aid of dual-layer hollow fiber technology for protein separation. Three types of immobilized metal affinity membranes (Cu²⁺, Ni²⁺ and Zn²⁺ forms) were developed in this work and they all exhibited enhanced protein separation performance compared to the as-spun hollow fiber in H⁺ form due to the strong affinity between transition metal counterions and target protein molecules. Ultimately, the high-purity target protein (>99%, w/w) could be achieved via the membrane in Cu²⁺ form.