用宫颈癌细胞Hela表面高表达G250抗原的单克隆抗体G250修饰非病毒基因载体,获得肿瘤靶向基因载体.通过注射G250杂交瘤细胞于小鼠腹腔,制备富含G250mAb的腹水,用正辛酸-硫酸铵沉淀法和Protein A Agarose分离纯化,获得高纯度的G250mAb.通过二硫键将PEI与G250mAb偶联,得到修饰的基因载体G250mAb-PEI,研究其转基因靶向性.结果表明,G250mAb-PEI对Hela细胞的基因转染具有显著的靶向性,对Hela细胞的转基因效率是肝癌细胞HepG2(G250阴性)的2倍;而对正常血管平滑肌细胞(SMC)的基因转染效率比Hela低近20倍,G250mAb修饰与否对SMC没有靶向性;对3T3细胞的毒性显著低于未修饰的PEI,表明G250mAb-PEI是一种高效、低毒和具有靶向性的基因载体.
The interactions of amino-terminated, and ethylenediamine core poly(amidoamine) (PAMAM) den-drimers and their derivatives with bovine serum albumin (BSA) were investigated by fluorescence spectroscopy. Ex-perimental results showed that the fluorescence intensity of BSA decreased after the addition of different modified den-drimers, and the extent of the fluorescence quenching caused by various modified dendrimers strongly depends upon the different functional groups on their surfaces. We also inves-tigated the influence of pH and ionic strength on the interac-tion between various modified dendrimers and BSA. Circu-lar dichroism (CD) spectroscopic measurements showed that the content of α-helix structure of BSA decreased after the addition of different modified dendrimers, which indicated that dendrimers induced changes in the secondary structure of BSA.
