Frontiers of Chemical Science and Engineering
Fabrication of high-capacity cation-exchangers for protein adsorption: Comparison of grafting-from and grafting-to approaches
|1. Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
2. Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
3. State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
In this work, we have synthesized two polymer-grafted cation exchangers: one via the grafting-from approach, in which sulfopropyl methacrylate (SPM) is grafted through atom transfer radical polymerization onto Sepharose FF (the thus resulting exchanger is referred as Sep- -SPM), and another via the grafting-to approach, in which the polymer of SPM is directly coupled onto Sepharose FF (the thus resulting exchanger is called as Sep- SPM). Protein adsorption on these two cation exchangers have been also investigated. At the same ligand density, Sep- -SPM has a larger accessible pore radius and a smaller depth of polymer layer than Sep- SPM, due to the controllable introduction of polymer chains with the regular distribution of the ligand. Therefore, high-capacity adsorption of lysozyme and -globulin could be achieved simultaneously in Sep- -SPM with an ionic capacity (IC) of 308 mmol·L . However, Sep- SPM has an irregular chain distribution and different architecture of polymer layer, which lead to more serious repulsive interaction to proteins, and thus Sep- SPM has a lower adsorption capacity for -globulin than Sep- -SPM with the similar IC. Moreover, the results from protein uptake experiments indicate that the facilitated transport of adsorbed -globulin occurs only in Sep- SPM and depends on the architecture of polymer layers. Our research provides a clear clue for the development of high-performance protein chromatography.