【作者】 王彬；

【导师】 潘君；

【作者基本信息】 重庆大学 ， 细胞生物学， 2008， 硕士

【摘要】 本研究工作的目的是以本室制备的新型聚乙二醇接枝聚乳酸（PPLA）为原料,通过自组装方式制备纳米微球,并研究其纳米微球的体外溶血性能。首先对PPLA在水中的自组装性能进行研究,探讨其作为纳米药物载体的可行性和稳定性。目测法得到其溶解度为（2.16～4.32）×10^-2 mg·mL^-1;荧光法得到聚合物的临界胶束浓度为1.12×10^-3 mg·mL^-1;透射电子显微镜显示该聚合物在水中的自组装聚集体为纳米级球形。动态激光光散射测试纳米微球的粒径和Zeta电位发现:在微球的制备过程中,聚合物的亲/疏水性比例、水相接枝及水溶液的pH值对其影响显著;而制备后,稀释和冷冻对其无显著影响,改变微球的环境pH值至酸性出现聚集,至碱性无显著影响。研究结果显示,该聚合物在水和磷酸钠盐缓冲液中可形成稳定的纳米微球,通过微球的制备条件和存在环境可控制其粒径及Zeta电位。此外,我们采用FITC标记牛血清白蛋白（FITC-BSA）为模型蛋白,测试了其纳米微球对非特异性蛋白质的吸附,结果显示与聚乳酸（PLA）微球相比,PPLA明显降低了对FITC-BSA的吸附。研究利用制备的不同粒径及浓度的PPLA纳米微球,探讨了粒径及纳米微球浓度对红细胞溶血性的影响,结果显示,浓度越小溶血率越小,粒径为200～960.8nm的微球的临界溶血浓度范围为1.5～2.0 mg·mL^-1;在相同浓度下,粒径越大溶血率越小。以胰岛素为亲水蛋白药物模型,制备了载药PPLA纳米微球,发现水相介质对胰岛素的包裹率、载药纳米微球的粒径和Zeta电位有一定影响。最后,利用包裹胰岛素的纳米微球,研究了其溶血性能,并与PPLA纳米空球、胰岛素的溶血性能比较;研究结果显示包裹胰岛素的纳米微球溶血率极低,比PPLA纳米空球和相当于完全释放后得到的胰岛素浓度的溶血率都低。综上所述,PPLA具有明显的自组装性质,可在水相介质中自发或包裹药物形成纳米微球,其空球的溶血性能与粒径相关;能有效包裹胰岛素,并实现缓释,包裹胰岛素后微球的溶血率比空球和药物本身都低,结果显示了PPLA在药物缓释方面的潜在价值。更多还原

【Abstract】 In this study, nanoparticles encapsulated with or without insulin were prepared via the self-assembly in aqueous medium with polyethylene glycol-graft-poly （lactic acid） （PPLA） as raw material. Their hemolysis properties were investigated. The solubility ofPPLA in water was （2.16～4.32）×10^-2 mg·mL^-1 according to eye judgment. The critical micelle concentration was 1.12×10^-3 mg·mL^-1 obtained from fluorospectrophotometer. The self-assembled aggregates of PPLA in water were nanoscale spheres observed by transmission electron microscope. The particle size and zeta potential tests by dynamic light scattering revealed that during preparation, the ratio of hydrophi-licity/hydrophob-icity, the aqueous medium and the pH had great influences; while dilution, freezing and pH change to basic condition had no effect after preparation, but pH change to acidic condition precipitated nanopaticles. The results indicated the particle size and zeta potential of PPLA nanoparticles could be easily controlled via the changes of condition in or after preparation. The anti-non-specific protein adsorption property of PPLA nanoparticles was confirmed by the FIY+TC-BSA absorption tests compared with particles of PLA.With the nanoparticles of various concentration and particle size, the % hemolysis were investigated. The results demonstrated that the particles size had great influences in the % hemolysis besides the concentration. The critical hemolysis concentration was 1.5～2.0 mg·mL^-1, at which the % hemolysis was just above 5%.Insulin loaded PPLA nanoparticles were prepared by the self-assembly in aqueous medium. They got good loading rate and controlled release results. The % hemolysis of insulin loaded PPLA nanoparticles were lower that the plain PPLA nanoparticles prepared in the same condition and than the insulin with the same concentration resulted from 100% release of insulin-loaded nanoparticles.All of the results suggested the postential applications of PPLA in drug delivery.更多还原