The invention provides a fully-dissociable type
polyethylene glycol-poly(L-glutamate-gamma-benzyl ester)-polyethyleneimine
copolymer as well as a synthesizing method and application thereof. The method comprises the following steps: performing
cystamine modification on terminated methoxy
polyethylene glycol; initiating a ring-opening
polymerization of gamma-benzyl ester-L-glutamate-N-carboxyanhydride by utilizing the terminated amine of the terminated methoxy
polyethylene glycol; connecting the product in the ring-opening
polymerization and polyethyleneimine by utilizing 2,2'-dithio-diethyl
isocyanate by virtue of an
addition reaction to obtain the target product. According to the method, the synthesized
copolymer is amphipathic, can be self-assembled to form nano-particles; chemotherapeutic medicines and genetic medicines can be simultaneously loaded to the
copolymer when the copolymer is used as a medical vector; the copolymer can be completely dissociated and disintegrated by responding
glutathione and other reductive substances, so that the vector can escape from
endosome to
cytoplasm, medicines can be quickly released, and the
treatment effect can be improved. The method can be used for controlling the molecular weight and length of each fragment in the segmented copolymer, is mild in reaction condition, and is suitable for more
medicine types.