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.