A novel polymer-grafted hydrophobic charge-induction chromatographic resin for enhancing protein adsorption capacity

Hydrophobic charge-induction chromatography (HCIC) is a developing technology for antibody purification. To enhance the protein adsorption capacity, a novel polymer-grafted HCIC resin was developed, in which the surface-initiated activator generated by electron transfer (AGET) atom transfer radical polymerization (ATRP) was explored as a controlled polymerization technique to reconstruct matrix structure and ligand distribution. Using poly(glycidyl methacrylate, GMA) as grafting polymer and 2-mercapto-1-methyl-imidazole (MMI) as functional ligand, poly(GMA)-grafted HCIC resins were prepared with series of grafting and ligand densities. Adsorption behaviors of human immunoglobulin G (hIgG) on the prepared resins demonstrated the necessity of controlling grafting and ligand density. Saturated adsorption capacity (Q(m)) and effective pore diffusivity (D-e) reached the maximum under medium ligand density when the grafting density was kept constant. The highest Q(m) and D-e values were found under the highest grafting density, which were 73% and 7.17 times higher than the non-grafted resin, respectively. Column breakthrough tests indicated that the dynamic binding capacity of the resin with optimized grafting density and ligand density was up to 34.6 mg/g when linear velocity was 300 cm/h, which was 86.3% higher than dextran-grafted resin. The resin was then used to separate hIgG from a protein mixture (hIgG/human serum albumin = 1:4), high purity (>99%) and recovery (>90%) of hIgG were found with 50 cycle reuses, which verified the selectivity and robustness of G-MMI resin prepared. In general, the surface-initiated AGET ATRP provides a controlled grafting strategy to improve protein binding capacity for chromatographic separation, and new resins developed have great potential in large-scale protein purification applications. (C) 2016 Published by Elsevier B.V.