High-capacity chromatographic packings for protein adsorption are the material prerequisite for the development of efficient protein chromatography processes. In this work

random copolymer-grafted cation-exchangers for protein adsorption were synthesized by grafting 3-sulfopropyl methacrylate and methyl methacrylate (MMA) to Sepharose Fast Flow via atom transfer radical polymerization

and lysozyme and antibody adsorption on to these cation-exchangers was investigated. In case of a given total concentration of the monomers for the grafting reaction

the pore radii of the copolymer-grafted cation-exchangers increased with an increase of MMA concentration

indicating a typical characteristic of a decreasing depth of polymer layer and gradual collapse of the random copolymers. Adsorption equilibria showed that the adsorption capacity for lysozyme was dominated by ionic capacity of the cation-exchangers whilst for antibody it was related to pore radius and corresponding the change in depth of polymer layer. With an increase in depth of polymer layer

there was stronger steric excluded interaction between antibody and polymer layer

and thus decreasing the adsorption capacity for antibody. Moreover

the results demonstrated that the adsorption capacities for proteins on random copolymer-grafted cation-exchangers were improved by optimizing the conformation of random copolymer chains.The adsorption capacities for antibody and lysozyme reached 237 and 380 mg·g-1 in the optimized random copolymer-grafted cation exchangers

respectively. The research revealed that both layer depth of copolymer and protein binding were also regulated by ionic strength in copolymer-grafted cation-exchangers.