共聚物接枝蛋白离子交换色谱介质制备及性能

高容量蛋白质色谱介质是色谱过程高效化的材料基础和重要前提。采用原子转移自由基聚合（ATRP）技术，以甲基丙烯酸3-磺酸丙酯钾和甲基丙烯酸甲酯（MMA）为单体化合物合成了多种无规共聚物接枝离子交换色谱介质，并对其蛋白质吸附性能进行研究。单体总浓度一定情况下共聚物接枝色谱介质孔道半径（r_pore）随MMA浓度升高而增大，反映出接枝共聚物链渐趋塌陷的特征。蛋白质吸附结果表明，溶菌酶吸附容量取决于介质的离子交换容量；而抗体吸附容量则与rpore及相应的聚合物层厚度变化密切相关。随着聚合物层厚度的增大，聚合物层对抗体的空间排阻作用增强，抗体吸附容量下降。此外，引入MMA优化共聚物分子链可显著提高蛋白质吸附量，在SEP-gS30/M30介质中抗体和溶菌酶的饱和吸附量分别达到237 mg·g^-1和380 mg·g^-1。无规共聚物接枝离子交换色谱介质孔道内聚合物层厚度和蛋白质吸附也受无机盐浓度调控。

Synthesis and characterization of copolymer-grafted cation-exchangers for protein adsorption

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.