Polylysine-modified Polyethylenimines as siRNA Carriers for Effective Tumor Treatment

Polyethylenimine-poly（L-lysine） （PEI-PLL） copolymer was synthesized via ring-opening polymerization of L-lysine N-carboxyanhydride （Lys（Z）-NCA） initiated by PEI. The complexation of PEI-PLL with siRNA was studied by particle size and zeta potential measurements. The flow cytometric analysis and confocal imaging showed its excellent intracellular trafficking ability. PEI-PLL displayed higher gene silencing efficiency and lower cytotoxicity than commercial PEI-25k in vitro. In the antitumor study, PEI-PLL was further combined with siVEGF and showed obviously tumor inhibition effect for the treatment of CT26 tumor model. Therefore, PEI-PLL is a promising siRNA carrier candidate for further antitumor treatment in vivo.