温敏梳状嵌段共聚物对PS微球阻抗蛋白吸附作用的研究

采用可逆加成断裂链转移聚合(RAFT)方法和大分子单体技术,制备了温敏性聚N-异丙基丙烯酰胺(PNIPAM)-聚乙烯基吡咯烷酮(PVP)与PNIPAM-聚氧化乙烯(PEO)梳状嵌段共聚物,这些共聚物具有PVP或PEO支链.以溶菌酶为蛋白模型研究了所得共聚物对聚苯乙烯(PS)微球表面蛋白吸附的抑制作用.通过絮凝实验、激光散射法表观粒径测定、电泳迁移率测定及蛋白吸附量的定量数据比较了不同梳状结构的抗蛋白吸附效果.结果表明,预吸附梳状嵌段共聚物可有效阻抗蛋白吸附,亲水支链增加阻抗性能提高,即使环境温度高于PNIPAM的相转变温度也能阻抗蛋白吸附.透射电镜和共聚物胶体粒径测试表明,梳状嵌段共聚物阻抗蛋白吸附的机制是预吸附后PVP或PEO亲水支链在微球表面形成了阻隔层.通过PS微球的变温絮凝实验可评价预吸附聚合物的抗蛋白吸附性能,快速获得定性结果.

THE EFFECT OF TEMPERATURE-SENSITIVE COMB-BLOCK COPOLYMERS ON PROTEIN ADSORPTION RESISTANCE OF POLYSTYRENE MICROSPHERES

Thermo-sensitive poly(N-isopropylacrylamide)(PNIPAM)-poly(N-vinylpyrrolidone)(PVP)and PNIPAM-poly(ethylene oxide)(PEO)comb-block copolymers with PVP and PEO hydrophilic branches,respectively,were synthesized using RAFT polymerization of NIPAM and PVP or PEO macromonomers.Polystyrene(PS)microspheres were treated in aqueous suspension with different copolymers obtained to allow polymer adsorbing on PS microsphere surface.Protein adsorption resistance of the PS microsphere with pre-adsorbed copolymer was evaluated,using lysozyme as the model protein,by flocculating test,particle coagulation(by dynamic light scattering),electrophoretic mobility measurement and quantitative analysis of protein adsorption.It was found that pre-adsorption of the comb-block copolymer on PS microsphere surface could effectively inhibit protein adhesion to the surface.A larger number of hydrophilic branches in the copolymer resulted in a better protein resistance both at room temperature and at temperatures higher than the LCST of PNIPAM.Transmission electron microscopy and dynamic light scattering measurements of the copolymer colloids confirmed that the hydrophilic branches formed an outer adsorb-layer and provided resistance to protein when the copolymer adsorbed on PS microsphere surface.Moreover,flocculation tests on heating and cooling of PS microsphere suspension in the presence of protein provided a simple and effective method to qualitatively evaluate the protein resistance of the polymers used for pre-adsorption treatment.