中文摘要：

目的：制备聚乙烯亚胺（ PEI）-黄芪多糖（ RAP）共聚物，探讨其作为非病毒基因载体的可行性。方法：采用氮丙啶法、高碘酸钾-PEI法以及羰基二咪唑-PEI法制备PEI-RAP。利用红外光谱鉴定3种方法所得产物的结构表征。通过琼脂糖凝胶电泳以及粒径和Zeta电位的测定考察PEI-RAP与质粒DNA的相互作用。 MTT法考察PEI-RAP载体的细胞毒性。 PEI-RAP负载绿色荧光表达载体pEGFP转染MCF-7、Hela和SMMC-7721细胞株观察转染效能。结果：通过氮丙啶法成功地将PEI接枝在RAP上，但是另外2种方法未得到目标产物。琼脂糖凝胶电泳结果表明PEI-RAP可以通过静电作用负载质粒 DNA。当PEI-RAP与pEGFP 质量比为12砄1时，复合物粒径为156．61 nm，电位为＋26．89 mV。 PEI-RAP载体无细胞毒性。体外转染实验表明，PEI-RAP可将pEGFP高效转染至MCF-7、Hela、SMMC-7721细胞。结论：成功制备了PEI-RAP共聚物，该共聚物是一种具有潜在应用前景的新的非病毒基因载体。

英文摘要：

To prepare polyethylenimine-radix astragali polysaccharide （PEI-RAP） copolymer and investigate the efficiency of PEI-RAP to transfect tumor cells in vitro .Met hods： PEI-RAP copolymers were prepared with three different methods, polymerization of aziridine, KIO4-PEI reactions and CDI-PEI reactions.The products were characterized using FT-IR.The interaction of PEI-RAP with DNA was investigated using particle size analysis , Zeta-potential measurements and gel electrophoresis assay .MTT method was used to detect the cytotoxicity of PEI-RAP.PEI-RAP was used to deliver pEGFP in three tumor cells, MCF-7, Hela and SMMC-7721 cell lines.Results：PEI-RAP was prepared by polymerization of aziridine successfully , while the other two methods were failed .Agarose gel retardation assay suggested that PEI-RAP could bind and condense plasmid DNA efficiently .When the mass ratio of PEI-RAP to the pEGFP was 12：1,the size and the Zeta potential of the complexes were 156.61 nm and ＋26.89 mV.The vector PEI-RAP showed no cytotoxicity .The reporter protein assay showed that pEGFP delivered by PEI-RAP could express green fluorescent protein efficiently in three tumor cells in vitro . Conclusion：The prepared PEI-RAP copolymer could be a promising non-viral gene delivery vector.