Novel polymersomes based on amphiphilic graft polyphosphazenes and their encapsulation of water-soluble anti-cancer drug

A series of amphiphilic graft polyphosphazenes with hydrophilic weight fraction ranging from 0.40 to 0.55 were synthesized. These copolymers could self-assemble into distinct aggregates in aqueous solutions. Spherical micelles were observed for the copolymer sample with higher hydrophilic weight fraction. However, when the hydrophilic weight fractions decreased to less than 0.50, vesicle-like polymersomes were formed. Doxorubicin hydrochloride (DOX·HCl), a water-soluble anti-cancer drug, was successfully loaded into the aqueous core of polymersome, which was clearly observed by transmission electron microscopy. The in vitro release of DOX·HCl from polymersome carries further confirmed its encapsulation. In addition, the cytotoxicity of DOX against HepG2 cells was significantly enhanced via polymersome delivery. These results suggest that amphiphilic graft polyphosphazenes could be used for the delivery of water-soluble drugs as polymersome vehicles.