Preparation of Degradable Polymeric Nanoparticles with Various Sizes and Surface Charges from Polycarbonate Block Copolymers

ABA-type polycarbonate block copolymers with pendant vinyl ether and benzyl functionalities were synthesized by sequential ring-opening polymerization of functional cyclic carbonate monomers using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an organobase catalyst. The vinyl ether moieties on the resulting block copolymers were readily conjugated with 3-mercaptopropionic acid, cysteamine hydrochloride, and L-cysteine hydrochloride monohydrate through thiol-ene “click” reactions, yielding anionic, cationic, and zwitterionic self-assembled nanoparticles, respectively, in corresponding buffers. The effect of pH on the size and surface charge of nanoparticles were examined. [Figure not available: see fulltext.].