物理化学学报 >> 2010, Vol. 26 >> Issue (02): 359-366.doi: 10.3866/PKU.WHXB20100207

催化和表面结构 上一篇    下一篇

接枝微球PMAA-HEMA/NVP对溶菌酶的吸附行为与吸附机理

付红艳, 高保娇, 牛庆媛   

  1. 中北大学化学工程系, 太原 030051
  • 收稿日期:2009-07-22 修回日期:2009-11-05 发布日期:2010-01-26
  • 通讯作者: 高保娇 E-mail:gaobaojiao@126.com

Adsorption Behavior and Mechanism of Grafted PMAA-HEMA/NVP Microspheres toward Lysozyme

FU Hong-Yan, GAO Bao-Jiao, NIU Qing-Yuan   

  1. Department of Chemical Engineering, North University of China, Taiyuan 030051, P. R. China
  • Received:2009-07-22 Revised:2009-11-05 Published:2010-01-26
  • Contact: GAO Bao-Jiao E-mail:gaobaojiao@126.com

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摘要：

采用反相悬浮聚合法制备了甲基丙烯酸羟乙酯(HEMA)与N-乙烯基吡咯烷酮(NVP)的交联共聚微球HEMA/NVP, 然后采用“接出”法, 实施了甲基丙烯酸(MAA)在交联微球表面的接枝聚合, 制得了接枝微球PMAA-HEMA/NVP. 以溶菌酶(LYZ)为模型碱性蛋白, 深入研究了接枝微球PMAA-HEMA/NVP对碱性蛋白的吸附性能与吸附机理. 测定了微球PMAA-HEMA/NVP的zeta电位, 考察了PMAA接枝度、介质pH值及离子强度等因素对体系吸附性能的影响. 结果表明, 在较大的pH范围内, 接枝微球PMAA-HEMA/NVP的zeta电位为绝对值较大的负值, 即其表面携带有高密度的负电荷. 在强静电相互作用的驱动下, 接枝微球PMAA-HEMA/NVP对溶菌酶表现出很强的吸附能力. 随介质pH值的增高, 接枝微球对溶菌酶的吸附容量呈现先增大后减小的变化趋势, 在与溶菌酶等电点接近的pH值处(pH=9), 具有最大的吸附容量(90 mg·g-1); 离子强度对接枝微球的吸附能力也有较大的影响, 当pH<9时, 溶菌酶吸附容量随NaCl浓度的增高而减小; 当pH>9时, 吸附容量随NaCl浓度的增高而增大.

关键词: 聚甲基丙烯酸, 聚合物接枝微球, 碱性蛋白质, 溶菌酶, 吸附机理

Abstract:

The crosslinking copolymerization of 2-hydroxyethyl methacrylate (HEMA) and N-vinylpyrrolidone (NVP) was performed using the inverse suspension polymerization method resulting in crosslinked HEMA/NVP microspheres. Subsequently, the graft polymerization of methacrylic acid (MAA) was conducted using the“grafting from”method and the grafted PMAA-HEMA/NVP microspheres were obtained. The adsorption property and adsorption mechanism of the grafted microspheres were investigated in depth using lysozyme (LYZ) as a basic protein model. The zeta potential of the grafted microspheres was determined. Several factors that affected the adsorption property of the system such as the pH of the medium, the grafting degree of the microspheres and the ionic strength were examined. Experimental results indicate that in a wide pH range, the zeta potential of the grafted PMAA-HEMA/NVP microspheres has a large negative value. Therefore, a high density of negative charge is present on the surfaces of the grafted microspheres. The strong electrostatic interaction results in which the grafted PMAA-HEMA/NVP microspheres exhibit very strong adsorption ability toward lysozyme. The adsorption capacity of the grafted microspheres for lysozyme initially increases and then decreases as the pH increases and a maximumadsorption (90 mg·g-1) is found at pH=9, which is close to the isoelectric point of lysozyme. The ionic strength affects the adsorption property of the grafted microspheres greatly. As pH<9, the adsorption capacity of lysozyme decreases as the NaCl concentration increases, whereas as pH>9, the adsorption capacity of lysozyme increases as the NaCl concentration increases.

Key words: Polymethacrylic acid, Grafted polymeric microspheres, Basic protein, Lysozyme, Adsorption mechanism