功能微球PEI-CPGMA的制备及其对胆红素的吸附特性

Preparation and Bilirubin Adsorption Property of Functional Microsphere PEI-CPGMA

以乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,采用悬浮聚合法制备了平均粒径为100μm的交联聚甲基丙烯酸缩水甘油酯(CPGMA)微球,然后通过胺基与环氧键之间的开环反应,将聚乙烯亚胺(PEI)偶合接枝在微球表面,制得了表面接枝PEI的功能微球PEI-CPGMA。研究了功能微球对胆红素的吸附性能,考察了接枝度、介质pH、离子强度等因素对微球吸附性能的影响。静态吸附实验结果表明:功能微球对胆红素具有强吸附能力,等温吸附满足Freundlich吸附方程,饱和吸附量可达14.1mg/g;介质的pH对微球吸附性能有很大的影响,在近中性(pH=6)溶液中,接枝微球对胆红素的吸附能力最强,而在酸性与碱性溶液中吸附能力都比较弱;离子强度对吸附作用表现出微弱的增效作用;微球表面PEI的接枝度越高,吸附能力越强。

Microbeads of poly glycidyl methacrylate （CPGMA） were synthesized with an average diameter of 100 μm adopting suspension method with ethylene glycol dimethacrylate as crosslinking agent, polyethylenimine （PEI） was then grafted on the surface of the CPGMA microsphere via the ring-opening reaction between the epoxy groups of PGMA and the amino groups of PEI, to form microspheres of PEI-CPGMA. The adsorption property of the microsphere for bilirubin was studied, and the effects of various factors, such as pH value, ionic strength of the medium and the grafting degree of PEI, on the adsorption property of microspheres were examined. The static adsorption experiment results show that PEI-CPGMA microspheres have strong adsorption towards bilirubin. The strong adsorption is attributed to the electrostatic interaction between the protonized amino groups of PEI and the dissociated carboxyl groups of bilirubin. The isothermal adsorption can be fitted to Freundlich equation, and the saturated adsorption can reach up to 14. 1 mg/g. The pH value of the aqueous solution has great effect on the adsorption property of PEI-CPGMA microsphere. In near neutral solution （pH=6）, the adsorption reachs maximum,while decreased in either acidic or basic solutions. Ionic strength of the medium has slight effect on the adsorption property of PEI-CPGMA microsphere .