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通过氨基引发聚丁二酰亚胺(PSI)开环反应,制备了系列侧链含氨乙基和咪唑丙基的聚(L-天冬酰胺)共聚物(P1～P5).该系列聚合物不仅具有极低的细胞毒性,而且随侧链中咪唑取代基含量的增加,聚合物在pH 5～8范围内缓冲能力显著提高.通过凝胶电泳、粒径和电位分析等研究了聚合物与质粒DNA的相互作用.结果表明,所有聚合物均可以在较低N/P比有效结合DNA.在N/P比高于5时,形成粒径在100 nm以下、表面电荷为+20 mV左右的稳定复合物纳米粒子.聚合物介导荧光素酶基因(pGL-3)和增强型绿色荧光蛋白基因(pEGFP-C1)体外转染293T细胞和COS-7细胞的结果表明,侧链中引入咪唑取代基显著提高了聚合物的转染能力.通过优化侧链氨基/咪唑取代基比例,获得转染效率最高的聚合物P4.P4介导pGL-3和pEGFP-C1在细胞中的表达与聚乙烯亚胺(PEI)相当、甚至是PEI的2～3倍.
A series of poly (L-asparagine) copolymers (P1 ~ P5) with aminoethyl and imidazolyl groups on their side chains were prepared by amino-initiated polysuccinimide (PSI) ring opening reaction. Not only has very low cytotoxicity, but also increases the buffer capacity of the polymer in the range of pH5 ~ 8 with the increase of the content of imidazole substituent in the side chain.Studied the relationship between the polymer and the polymer by the gel electrophoresis, particle size and potential analysis The results showed that all the polymers could efficiently bind DNA at a low N / P ratio.When the N / P ratio was above 5, the particle size was below 100 nm and the surface charge was about +20 mV (PGL-3) and enhanced green fluorescent protein (pEGFP-C1) transfected 293T cells and COS-7 cells in vitro results showed that the introduction of the side chain Imidazole substituent significantly improve the transfectivity of the polymer by optimizing the ratio of side chain amino / imidazole substituents, to obtain the highest transfection efficiency of the polymer P4.P4-mediated expression of pGL-3 and pEGFP-C1 in cells and Polyethyleneimine (PEI) equivalent, or even PEI 2 to 3 times.