National Key Lab of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
National Key Lab of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
J Chromatogr A. 2014 May 23;1343:109-18. doi: 10.1016/j.chroma.2014.03.064. Epub 2014 Apr 1.
High hydrophilicity of gigaporous microspheres based on a copolymer of poly(glycidyl methacrylate)-co-divinyl benzene (PGMA-DVB) was successfully realized through coating the branched polyethyleneimine (PEI) in PGMA-DVB microspheres. PEI with various molecules weights and different branching agents were identified in terms of protein recovery as evaluation approach. For this evaluation, PEI600 (Mw=600) and poly (ethylene glycol) diglycidyl ether (PEGDE, Mw=400) were used as modification agent and branching agent, respectively. The modified microspheres showed good permeability and revealed a certain mechanical strength. After modification, the protein recovery increased from 40% to >90%. The protein recovery increased with the branched generations and the first and second generations could give the protein recovery of 93% and 96%, respectively. Meanwhile, the ionic capacity also showed a rising trend in the range of 0.11-0.32mmol/mL with the branched generations. But the dynamic binding capacity of protein (bovine serum albumin, BSA as the model protein) increased at first and then decreased. Analysis of the dry microspheres structure by mercury intrusion method as well as observation of the branched PEI on PGMA-DVB membrane in aqueous solution indicated that excess PEI chains with the extended state in the second generation would block the small pores and decrease the accessible surface area. Therefore, the protein capacity on the second generation, on the contrary, was lower than that on the first generation. Meanwhile, it was found that the PEI chains in the modified microspheres changed their construction from the extended to the collapsed state with increase of NaCl concentration. And the corresponding pore size of the modified microspheres increased with salt concentration through low-field nuclear magnetic resonance. Dynamic binding capacity of proteins on the modified supports did not significantly change with increase of the flow rate. The media showed good performance for separation three model proteins at high flow rate of 1084cm/h. This modified gigaporous microspheres had a large potential in application for rapid separation of biomolecules.
通过在 PGMA-DVB 微球中包覆支化的聚乙烯亚胺（PEI），成功地实现了基于聚（甲基丙烯酸缩水甘油酯）-共-二乙烯基苯（PGMA-DVB）的大孔微球的高亲水性。以蛋白质回收率为评价方法，研究了不同分子量和不同支化剂的 PEI。为此评价，分别使用 PEI600（Mw=600）和聚乙二醇二缩水甘油醚（PEGDE，Mw=400）作为改性剂和支化剂。改性微球具有良好的渗透性和一定的机械强度。改性后，蛋白质回收率从 40%提高到>90%。蛋白质回收率随支化代的增加而增加，第一代和第二代的蛋白质回收率分别为 93%和 96%。同时，离子容量也随支化代的增加呈上升趋势，在 0.11-0.32mmol/mL 范围内。但蛋白质（牛血清白蛋白，BSA 作为模型蛋白）的动态结合容量先增加后减少。通过压汞法分析干微球结构以及观察水溶液中支化 PEI 在 PGMA-DVB 膜上的状态，表明第二代中处于伸展状态的过量 PEI 链会堵塞小孔，减少可及表面积。因此，第二代的蛋白质容量反而低于第一代。同时，发现随着 NaCl 浓度的增加，改性微球中的 PEI 链从伸展状态转变为塌陷状态。并且，通过低场核磁共振，改性微球的相应孔径随盐浓度的增加而增加。随着流速的增加，蛋白质在改性载体上的动态结合容量没有显著变化。该改性大孔微球在高流速 1084cm/h 下对三种模型蛋白质的分离具有良好的性能。这种改性大孔微球在快速分离生物分子方面具有很大的应用潜力。
