Division of Environmental Science and Engineering, Faculty of Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
ACS Appl Mater Interfaces. 2010 Jan;2(1):203-11. doi: 10.1021/am900654d.
A novel electrolyte-responsive membrane, RC-g-PSBMA, was successfully prepared from regenerated cellulose (RC) membrane through surface-initiated atom transfer radical polymerization (ATRP) of a zwitterionic monomer, sulfobetaine methacrylate (SBMA). Different degrees of polymerization for the grafted SBMA polymers (i.e., PSBMA) on the RC membrane were easily obtained by adjusting the ATRP reaction conditions. The electrolyte-responsive behavior of RC-g-PSBMA was first evaluated through the permeation experiments with sodium chloride (NaCl) solutions of different concentrations. It was found that the permeability of RC-g-PSBMA showed a clear dependence on NaCl concentration in the solutions. To further examine the potential of RC-g-PSBMA for protein purification, bovine serum album (BSA) was chosen as a model protein and polystyrene nanoparticles (NPs) of different sizes were used as representative impurities in the solutions. The rejection rates of BSA and NPs by RC-g-PSBMA were examined with the solutions containing BSA and NPs at different NaCl concentrations. The results showed that the rejection rates of BSA were at a very low level regardless of the concentration of NaCl in the solutions, indicating that the membrane allowed BSA to permeate. However, the rejection rates of NPs of different sizes by RC-g-PSBMA changed remarkably with the concentration of NaCl in the solutions. The study has demonstrated the possibility to separate BSA from NPs of different sizes by using the same membrane but simply altering the concentration of NaCl in the solutions. Membranes with such properties will have a great potential for protein purification as well as for many other separation applications.
一种新型的电解质响应膜 RC-g-PSBMA 通过再生纤维素 (RC) 膜表面引发原子转移自由基聚合 (ATRP) 成功制备得到，使用的单体为两性离子单体磺酸甜菜碱甲基丙烯酰胺 (SBMA)。通过调整 ATRP 反应条件，可以很容易地获得 RC 膜上接枝 SBMA 聚合物（即 PSBMA）的不同聚合度。通过不同浓度的氯化钠 (NaCl) 溶液的渗透实验首次评估了 RC-g-PSBMA 的电解质响应行为。结果表明，RC-g-PSBMA 的渗透性明显依赖于溶液中的 NaCl 浓度。为了进一步考察 RC-g-PSBMA 在蛋白质纯化方面的潜力，选择牛血清白蛋白 (BSA) 作为模型蛋白，不同尺寸的聚苯乙烯纳米颗粒 (NPs) 作为溶液中的代表性杂质。通过含有不同浓度 NaCl 的溶液，考察了 RC-g-PSBMA 对 BSA 和 NPs 的截留率。结果表明，无论溶液中 NaCl 的浓度如何，BSA 的截留率都非常低，表明膜允许 BSA 渗透。然而，RC-g-PSBMA 对不同尺寸 NPs 的截留率随溶液中 NaCl 浓度的变化而显著变化。该研究表明，可以通过使用相同的膜但简单地改变溶液中 NaCl 的浓度来分离不同尺寸的 BSA 和 NPs。具有这种特性的膜在蛋白质纯化以及许多其他分离应用中具有很大的潜力。
