摘要目的 研究聚酰胺-胺型树形分子(PAMAM)脂质体对人结肠癌细胞摄入和细胞毒性的影响.方法 以1,2-二油烯氧基-3-三甲氨基丙烷(DOTAP)和二油酰基磷脂酰乙醇胺(DOPE)为材料制备脂质体,将质粒PEGFP-N1与脂质体和PAMAM混合分别制备PAMAM脂质体/DNA转染复合物和PAMAM/DNA转染复合物.透射电镜观察转染复合物的形态、粒径,zeta电位分析仪测定载质粒纳米粒子的zeta电位,离心法和紫外分光分度仪测定载质粒纳米粒子的包封率,将上述两种载质粒纳米粒子转染人结肠癌细胞SW620、人乳腺癌细胞MCF-7、血管内皮细胞ECV304,流式细胞仪测定增强型绿色荧光蛋白(EGFP)基因的入胞量,MTT法对PAMAM脂质体/DNA复合物和PAMAM/DNA复合物的毒性进行评价.结果 PAMAM脂质体载质粒纳米粒子的粒径与PAMAM载质粒纳米粒子的粒径差异无统计学意义[(192±16)nm比(189±19)nm,P＞0.05],zeta电位前者高于后者[分别为(42±7)mV和(32±7)mV,P＜0.05],包封率两者之间差异无统计学意义[(82±7)%比(84±6)%,P＞0.05].PAMAM脂质体载质粒纳米粒子和PAMAM载质粒纳米粒子转染SW620、MCF-7、ECV304细胞后,PAMAM脂质体/DNA组细胞EGFP基因摄入量高于PAMAM/DNA组,差异有统计学意义(P＜0.05).前者细胞存活率高于后者,差异有统计学意义(P＜0.05).结论 脂质体修饰聚酰胺-胺型树形分子可提高基因转染细胞的效率,降低细胞毒性.

abstractsObjective To evaluate the effects ofpolyamidoamine dendrimer(PAMAM) liposome as gene carriers on the cellular uptake and its cytotoxicity in colonic cancer cell. Methods The liposome modified PAMAM was synthesized with liposome and polyamidoamine dendrimer. Plasmid PEGFP-N1 was mixed with the liposome-modified PAMAM or unmodified PAMAM to form nanoparticle complexes. The shape and size of the nanoparticle complexes were observed by transmission electron microscope and the zeta potential was measured by analytical tool. The encapsulating efficiency was determined by ultraviolet spectrophotometer in centrifuging method. After the cell lines SW620 ( colonic cancer cell), MCF-7 ( breast cancer cell), ECV304(vascular endothelial cell) were transfected by the two kinds of PAMAM nanoparticle complexes, the flow cytometry was used to determine the uptake of enhanced green fluorescent protein (EGFP) gene. The cytotoxicity of PAMAM liposome nanoparticles and PAMAM nanoparticles was evaluated by MTT assay. Results The diameter of liposome modified PAMAM complex was (192 ± 16) nm, and that of PAMAM complex was ( 189 ± 19) nm ( P ＞0. 05 ); and the zeta potential of liposome modified PAMAM complex was higher than that of PAMAM complex [(42 ± 7 )mV vs. (32 ± 7) mV, P ＜ 0. 05]. There was no significant difference in envelopment rate between the two groups [( 82 ± 7) % vs. (84 ± 6) %, P＞0.05].After the colonic cancer cell line SW620 was transfected with the two kinds of PAMAM nanoparticle complexes, the cellular uptake of the cells with the liposome-modified PAMAM complex was significantly higher than that of the cell with PAMAM complex(P＜0.05). The cellular survival rate of the cell lines with liposome-modified PAMAM complex was significantly higher than that of cell lines with PAMAM complex (P ＜0. 05). Conclusion The liposome modified PAMAM can improve gene transfection efficiency and suppress its cytotoxicity.