Synthesis and physicochemical characterization of a novel amphiphilic polylactic acid-hyperbranched polyglycerol conjugate for protein delivery

Amphiphilic copolymers with polylactic acid (PLA) chains grafted onto hyperbranched polyglycerol (HPG) have been synthesized and characterized. The copolymer nanoparticles with corona and core structure were formed by self-assembly in aqueous solution. The loading capacity and association efficiency were up to 23% and 86%, respectively. Protein release profiles with different copolymer compositions and BSA concentrations all showed a burst effect followed by a continuous release phase. The released BSA from the copolymer nanoparticles remained in its original structure over a period of 4 days, as testified by circular dichroism spectroscopy. Furthermore, cell viability research suggested good biocompatibility of the copolymer nanoparticles, which have a promising potential for protein delivery system. (C) 2009 Elsevier B.V. All rights reserved.