刺激响应双硒交联聚乙烯亚胺基因微载体

摘要

Four different diselenide-crosslinked polyethylenimine ( PEISeSe ) were successfully prepared by changing the dosage of cross-linker and reaction time. The influence of cross-linking level on the DNA conden-sation, proton buffer capacity and transfection efficiency were investigated. The results indicated that the pro-ton buffer capacity of PEISeSe was reduced with cross-linking level. All of the polycations could efficiently condense DNA into spherical particles with diameter of 150 nm at m(PEISeSe)/m(DNA)= 8. Moreover, diselenide bonds were easily cleaved in the presence of DTT. Cell culture results indicated that by adding chloroquine to exclude the limitation of lysosome escape, PEISeSe showed decreased cell cytotoxicity and effi-cient transfection. The proper reason was that the intracellular cleavage of diselenide bonds facilitated DNA re-lease and nuclear entry. The diselenide-crosslinked polycations had promising potential in redox-sensitive gene delivery.%以丙酸二硒醚为交联剂，通过调节交联剂的用量及反应时间，制备了4种双硒交联聚乙烯亚胺( PEISeSe)，研究了其对脱氧核糖核酸( DNA)缔合能力、质子缓冲能力和转染效率的影响。结果表明，随着交联程度的增大，质子缓冲能力降低。 PEISeSe能有效诱导DNA的缔合，当聚合物与DNA的质量比≧8时， PEISeSe/DNA组装体可形成150 nm的粒子。在模拟细胞内的还原性环境下，双硒键能有效断裂，显示出很好的响应特性。将氯喹与PEISeSe/DNA组装体同时加入到HEK293T细胞中，氯喹的存在有利于PEISeSe/DNA组装体逃离溶酶体。在细胞内高浓度还原型谷胱甘肽的作用下， PEISeSe交联聚合物可被降解为低分子量的PEI片段，有利于释放出DNA并进攻细胞核，提高转染率并降低毒性。