中文摘要：

目的：以增强型绿色荧光蛋白质粒（pEGFP）为报告基因，探讨影响壳聚糖（CS）介导的基因转染率的因素。方法：复凝聚法制备pEGFP／CS纳米粒，选用HEK293细胞，考察CS相对分子质量、CS中的氨基与pEGFP中的磷酸基的比值（N／P比）、纳米粒粒径、介质pH值和血清对转染率的影响。结果：相对分子质量5×10^3的CS获得较高转染率；转染率随N／P比增加而提高；介质pH≤6．8有利于转染；在230～1290nm范围，粒径对转染效率无影响；CS介导的转染不受血清影响。结论：CS相对分子质量、N／P比和介质pH值是影响转染率的因素，低相对分子质量水溶性CS有利于提高转染。

英文摘要：

Objective：To investigate the factors affecting in vitro transfection efficiency mediated by chitosan （CS） using the enhanced green fluorescent protein plasmid （pEGFP） as reporter gene. Methods：pEGFP/CS nanopanicles were prepared by the complex coacervation method. The effects of the molecular weight of CS,N/P ratio, panicle size of the uanoparticles, pH of transfection medium and the presence of serum on transfection efficiency were investigated in HEK293 cells. Results：The transfection efficiency of pEGFP/CS nanoparticles was found to be highest when the molecular weight of chitosan was 5 KDa or the pH of transfection medium was no more than 6.8. Moreover,the transfection efficiency was independent on the particle size in the range of 230 to 1 290 nm and was enhanced by the increase of N/P ratio. Furthermore, the presence of serum had no impact on the CS-mediated transfection efficiency. Conclusion： The molecular weight of CS, N/P ratio and pH of transfection medium were the important factors which would affect transfection efficiencies mediated by CS. Low molecular weight and watersoluble CS was advantageous to improving transfection efficiency.