PEI接枝聚甲基丙烯酸甲酯磁性微球的蛋白吸附性能研究

发布时间：2018-04-01 20:35

  本文选题：磁性微球　切入点：聚乙烯亚胺　出处：《河北大学》2017年硕士论文

【摘要】：磁性高分子微球具有粒径小,比表面大,易分离等优点,在酶的固定化方面有着重要的理论和实践意义。本文制备了聚甲基丙烯酸甲酯磁性微球(PMMA)并在其表面接枝修饰聚乙烯亚胺(PEI),研究了磁性微球的蛋白质吸附性能及其作为载体对脂肪酶的固定化效果。主要内容包括以下几个部分:第一,以甲基丙烯酸甲酯(MMA)为单体,采用悬浮聚合法制备了PMMA磁性微球,利用扫描电镜对其进行表征,发现其具有较好的单分散性和球形度,粒径分布在10-25μm之间。进而对微球进行酯解,红外光谱数据表明酯解后的微球表面携带大量羧基,化学滴定显示羧基含量为0.94 mmol/g。第二,利用微球表面的羧基为功能基团,将不同分子量的聚乙烯亚胺(PEI 600,PEI 1800,PEI 70000)接枝到微球上,并分别使其作为载体吸附模型蛋白BSA,考察了不同分子量PEI接枝微球对蛋白质吸附的影响,并与未接枝PEI的微球吸附性能进行了比较。结果显示,微球在接枝PEI后能够显著提高BSA的吸附量,且接枝PEI 1800的微球吸附量最高,PMMA酯解、PMMA-PEI 600、PMMA-PEI 1800、PMMA-PEI 70000等四种微球的吸附量分别为44 mg/g、54.1 mg/g、62.1 mg/g、47.4 mg/g。实验进一步研究了初始BSA浓度、pH值、离子强度、温度等因素对BSA吸附的影响。结果表明,增加离子强度会引起BSA吸附量下降,在pH=7.0,35℃下,磁性微球PMMA-PEI 1800对BSA吸附量达到最大67 mg/g。此外,吸附-解吸附实验表明,PMMA-PEI 1800具有良好的重复使用性。第三,以PMMA-PEI1800磁性微球为载体固定化脂肪酶Candida rugosa lipase(CRL),实验优化了固定化酶的条件,考察了固定化脂肪酶的最适温度、最适PH及其热稳定性和pH稳定性。与游离酶相比,固定化酶的最适温度、热稳定性、pH稳定性均得到了提高,且固定化酶的温度和PH适应范围比游离酶宽。结果显示,pH=7,温度为35℃,给酶量为4 mg时酶比活最大。
[Abstract]:Magnetic polymer microspheres have the advantages of small particle size, large specific surface, easy separation and so on. It has important theoretical and practical significance in immobilization of enzyme. In this paper, the poly-methyl methacrylate magnetic microspheres (PMMAs) were prepared and grafted onto the surface of polyvinyleneimide (PEI), and the protein adsorption properties of magnetic microspheres were studied. Its immobilization effect on lipase as a carrier. The main contents include the following parts: first, PMMA magnetic microspheres were prepared by suspension polymerization with methyl methacrylate as monomer and characterized by scanning electron microscope. The particle size was between 10 ~ 25 渭 m. Then the microspheres were hydrolyzed by ester. The IR spectra showed that the surface of the microspheres carried a large number of carboxyl groups, and the chemical titration showed that the carboxyl content was 0.94 mmol / g. Secondly, the carboxyl groups on the surface of the microspheres were used as functional groups. Polyethylene imine (PEI) with different molecular weight was grafted onto the microspheres and used as a carrier to adsorb the model protein BSA. The effects of different molecular weight PEI grafted microspheres on protein adsorption were investigated. Compared with the ungrafted PEI microspheres, the results showed that the adsorption capacity of BSA was significantly increased by the grafted PEI microspheres. The adsorption capacity of PMMA-PEI 600 and PMMA-PEI 1800O PMMA-PEI 70000 were 44 mg / g 54.1 mg / g / g ~ 62.1 mg / g ~ (-1) mg / m ~ (4) mg / g respectively. The effects of pH value of initial BSA concentration, ionic strength and temperature on the adsorption of BSA were further studied. The adsorption capacity of BSA decreased with increasing ionic strength. At pH = 7.0 ~ 35 鈩，

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