Synthesis of a carbon dioxide-based amphiphilic block copolymer and its evaluation as a nanodrug carrier

A series of novel amphiphilic block copolymers poly(propylene carbonate)-block-mono-methoxy poly(ethylene oxide) (PPC-b-MPEG) composed of hydrophobic PPC segments and various lengths of hydrophilic MPEG segments was synthesized via “Click Chemistry” between azido-terminated PPC and alkynyl-terminated MPEG. The structure of the copolymers was characterized by FTIR, 1H NMR and 13C NHR techniques. Chlorpyrifos (CHP) was encapsulated within micelles through diffusion dialysis method, leading to the formation of CHP-loaded PPC-b-MPEG micelles. The resulting micelles were characterized further by dynamic light scattering (DLS) and scanning electron microscope. The results indicated that PPC-b-MPEG could self-assemble into nanosized micelles with PPC cores and PEG shells in aqueous solution. And the size, zeta potential, morphology, critical micelle concentration of PPC-b-MPEG micelles can be altered by changing the lengths of the PEG segments. CHP was encapsulated into PPC-b-MPEG2k micelles with loading capacity of 9.02% and entrapment efficiency of 77.28%. These results suggested that PPC-b-MPEG micelles would be a potential carrier for controlled release.