【摘要】 以IDPI为偶联剂,由相对分子量2000的甲氧端基聚乙二醇(mPEG-2k)和5代聚酰胺-胺(PAMAM-G5)通过二步法合成了聚酰胺-胺-聚乙二醇(PAMAM-PEG)共聚物。红外光谱和1H NMR谱分析证实了共聚物的生成,并计算出2个共聚物的聚乙二醇(PEG)结合率分别为10%和30%。MTT法的结果发现,PEG修饰后共聚物的细胞毒性明显降低,随PEG结合率的提高,毒性下降更明显。凝胶阻滞电泳说明,PAMAM-PEG可以与DNA结合形成复合物。动态光散射的测定数据证明,当N/P≥50时,共聚物/DNA复合物的粒径在150～200 nm,zeta电位在10～25 mV。基因转染的结果表明,在N/P≤50时,PAMAM-PEG共聚物的基因转染率稍低于PAMAM-G5,但可以通过提高N/P值或延长转染时间的方法来提高转染率。综合考虑毒性和转染率,PAMAM-PEG-13比PAMAM-PEG-39的改性效果更好。更多还原

【Abstract】 Polyamidoamine-polyethylene glycol(PAMAM-PEG) copolymers were synthesized using IPDI as coupling reagent by two-step method.The copolymers were characterized by IR spectrum and 1H NMR spectrum,and the PEG conjugating ratios of the copolymers were calculated equal to 10% and 30% separately.MTT assay indicated that after PEGylation a lower cytotoxicity of the copolymers could be found,and with increasing PEG conjugating ratio the cytotoxicity decreased obviously.Agarose gel retardation assay demonstrated that PAMAM-PEG copolymers could be combined with DNA and PAMAM-PEG/DNA complexes were prepared by self-assembly.DLS measurement showed that when N/P≥50,the particle size of copolymer/ gene complexes was in a range of 150-200 nm,and the zeta potential was in a range of 10-25 mV.In vitro gene transfection illustrated that when N/P≤50,the gene transfection efficiency of PAMAM-PEG copolymers was a little less than that of PAMAM-G5,but the transfection efficiency can be raised by increasing N/P ratio or transfection time.Considering both cytotoxicity and transfection efficiency aspects PAMAM-PEG-13 was more effect than PAMAM-PEG-39 in PEGylation.更多还原