Preparation of microparticles composed of amphiphilic poly(?-glutamic acid) through hydrophobic interactions

A novel amphiphilic graft copolymer composed of poly(?-glutamic acid) (?-PGA) as a hydrophilic backbone and dodecylamine (DOA) as a hydrophobic side chain (?-PGA-DOA) was successfully synthesized by employing 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the coupling reagent. The grafting degree was stoichiometrically controlled by adjusting the feeding amounts of DOA and EDC in the reaction system. ?-PGA-DOA, with a grafting degree of 55%, self-assembled via hydrophobic interactions and formed microparticles (MPs; diameter of 13±3?µm) in an aqueous solution. These MPs possessed functional carboxylic groups and could be further modified with compounds such as drugs, proteins and peptides, and thus have great potential as vaccine carriers.