Characterization of complexes made of polylysine-polyleucine-polylysine and pDNA
Polylysine shows unique physical and biological abilities in its application. In this study, different kinds of tri-block co-polypeptides are used as gene delivery vector with hydrophobic polyleucine (L) in the middle and polylysine(K) on two sides. We explored their physical ability in aqueous solution as well as biological effect about gene transfection efficiency. After reaching their critical micelle concentration, it is found that these tri-block polypeptides could form vesicles, and the size of each sample is independent with concentration. The self-assemble of each kind tri-block co-polypeptide could obtain higher molecular weight vectors for gene delivery. After measuring their transfection efficiency and cell viability, these samples perform high gene transfer ability together with similar and low cytotoxicity. Additionally, pDNA binding strength test and zeta-potential assay reveal that addition of L part would reduce charge density of the vector chains and thus lower the binding strength, leading to the easier release of pDNA from complexes and the increase of transfection efficiency.