中文摘要：

本文研究了聚乙烯亚胺-胆固醇阳离子聚合物（PEI-Chol）基因载体的性能及其结合中性脂质、聚乙二醇修饰脂质微泡介导的基因传递系统（微泡/PEI-Chol/DNA）的体外细胞基因转染效率。采用胆固醇甲酰氯与聚乙烯亚胺（Mw1800）通过酰胺化制得PEI-Chol,并运用IR、1H NMR和MADI-TOF-MS（基质辅助激光解吸附电离串联飞行时间质谱）对其结构和分子量进行测定,平均相对分子质量约为2000。采用反相挥发法制备DPPC、DSPE-PEG2000和全氟丙烷构建的粒径为2～8μm的脂质微泡,并运用自组装技术将PEI-Chol/DNA复合物与微泡融合,构建微泡/PEI-Chol/DNA（bubble/PEI-Chol/DNA）基因转染系统;以pEGFP-Cl（enhanced green fluorescent protein,增强型绿色荧光蛋白）为报告基因,用凝胶滞留试验考察PEI-Chol的DNA压缩能力,同时在A549和MCF-7两种细胞中比较以PEI-Chol为核心构建的各种载体系统的细胞毒性、抗血清沉淀作用以及细胞转染效率。结果发现,当N/P比值为4以上时,PEI-Chol能有效压缩DNA;PEI-Chol和构建的微泡系统对A549和MCF-7两种细胞几乎没有毒性;本微泡介导基因转染系统,一方面降低PEI-Chol的毒性,提高抗血清蛋白沉淀作用,另一方面提高其基因转染效果。研究表明新型bubble/PEI-Chol/DNA是一种高效低毒的非病毒基因载体系统。

英文摘要：

The properties of polyethyleneimine-cholesterol cationic lipopolymer （PEI-Chol） as gene carries and its gene transfer efficiency in vitro with lipid microbubbles were presented in this paper.PEI-Chol lipopolymer was synthesized by linking cholesterol chloroformate to the amino groups of branched poly（ethyleneimine） （PEI） of 1 800.The structure and molecular weight of PEI-Chol were confirmed by IR,1H NMR and MADI-TOF-MS （matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry）,respectively.The average molecular weight of PEI-Chol was approximately 2 000.The gene delivery system of bubble/PEI-Chol/DNA was constructed by mixed PEI-Chol/pDNA （N/P 10∶1） complexes with lipid microbubbles （2-8 μm） which were prepared by DPPC,DSPE-PEG2000 and perfluoropropane with the reverse phase evaporation technique.pEGFP-Cl （enhanced green fluorescent protein） was used as report gene to investigate the DNA condensing ability of PEI-Chol lipopolymer by agarose gel electrophoresis.And their cytotoxicity and in vitro transfer efficiency of different complexes were compared with each other in A549 and MCF-7.The results indicated PEI-Chol lipopolymer can condense plasmid DNA when N/P ratio upto 4,PEI-Chol complexes and bubble/PEI-Chol/DNA complexes were nontoxic to A549 and MCF-7 when formulated at the N/P ratio of 10/1 as determined by MTT assay.This bubble/PEI-Chol/DNA delivery system provided good transfer efficiency with other desirable characteristics such as against-precipitation of plasma proteins.In conclusion,bubble/PEI-Chol/DNA complex is a novel non-viral gene delivery system.