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本文合成了一种α-环糊精(α-cyclodextrin,α-CD)与聚酰胺-胺(polyamidoamine,PAMAM)的接枝聚合物(Cy D-G1)。~1H核磁测试结果表明,每个环糊精分子上平均接枝了6.4个PAMAM-G1分子。凝胶电泳结果显示,Cy D-G1可以有效结合DNA,并保护DNA免于核酸酶DNase I的降解。当载体与DNA复合物的N/P比为40时,可以压缩DNA形成平均粒径为120 nm左右的粒子,复合物表面的zeta电位约为+21 m V。该复合物可以在血清存在的条件下保持粒子的完整性并在360 min内稳定性良好。与对照品PEI-25K载体相比,Cy D-G1在高浓度时仍表现出较低的细胞毒性。将Cy D-G1与市售Lipofectamine 2000和PEI-25K对比转染发现,Cy D-G1/DNA复合物在多种细胞系中具有较高的转染率,而且转染水平不受血清影响。通过激光共聚焦观察并结合流式细胞分析表明,该阳离子聚合物介导DNA可以在4 h内有效进入细胞核内。上述结果证明,该阳离子聚合物作为一种非病毒型基因传递系统具有优良的性能以及体内给药应用的潜在可行性。
In this paper, a graft polymer (Cy D-G1) of α-cyclodextrin (α-CD) and polyamidoamine (PAMAM) was synthesized. 1H NMR results showed that 6.4 PAMAM-G1 molecules were grafted onto each cyclodextrin molecule. The results of gel electrophoresis showed that Cy D-G1 can bind DNA effectively and protect the DNA from nuclease DNase I degradation. When the N / P ratio of the carrier to the DNA complex is 40, the DNA can be compressed to form particles with an average particle diameter of about 120 nm. The zeta potential on the surface of the complex is about +21 mV. The complex can maintain particle integrity in the presence of serum and is stable within 360 min. Compared to the control PEI-25K vector, Cy D-G1 still showed lower cytotoxicity at high concentrations. Transfection of Cy D-G1 with commercially available Lipofectamine 2000 and PEI-25K revealed that the Cy D-G1 / DNA complex had a higher transfection efficiency in a variety of cell lines and the transfection levels were not affected by serum. Laser confocal observation combined with flow cytometry analysis showed that the cationic polymer-mediated DNA can efficiently enter the nucleus within 4 h. The above results demonstrate the potential of the cationic polymer as a non-viral gene delivery system with excellent performance and in vivo drug delivery.