A tetra(L-lysine)-grafted poly(organophosphazene) for gene delivery

Abstract In order to develop a new gene delivery vector, a novel cationic poly(organophosphazene) was synthesized by stepwise nucleophilic substitutions of poly(dichlorophosphazene) with a hydrophilic methoxy-poly(ethylene glycol) (MPEG) as a shielding group and a branched tetra( l -lysine), LysLys(LysEt) 2 , as a cationic moiety. The cationic polymer has shown to form a polyplex by DNA condensation and very low in vitro cytotoxicity probably due to the shielding effect of MPEG, which provides a basis for improving the low gene transfection yield of cationic polyphosphazenes.