pDNA/poly( L ‐lysine) Polyplexes Functionalized with a pH‐Sensitive Charge‐Conversional Poly(aspartamide) Derivative for Controlled Gene Delivery to Human Umbilical Vein Endothelial Cells

An efficient endosome‐escaping function was integrated into the polyplex of plasmid DNA (pDNA) with poly( L ‐lysine) (PLys) to improve its gene transfection efficiency through electrostatic coating with charge‐conversional polymer (CCP). CCP showed charge‐conversional function responding to endosomal pH, leading to the release of pDNA/PLys polyplex into the cytoplasm. The cells took up the intact CCP‐integrated ternary polyplex, which exerted appreciably higher transfection efficiency with lower cytotoxicity than pDNA/PLys polyplex against human umbilical vein endothelial cells (HUVECs). This is consistent with the facilitated endosomal escape of the CCP‐integrated ternary polyplex compared to the pDNA/PLys polyplex as directly observed with confocal laser‐scanning microscopy.