• hyperbranched poly(amine-ester);
  • poly(lactide);
  • amphiphilic copolymer;
  • bovine serum albumin;
  • protein delivery system


A series of hyperbranched poly(amine-ester)-co-D,L-lactide (HPAE-co-PLA) copolymer were synthesized by ring-opening polymerization of D,L-lactide with Sn(Oct)2 as catalyst to a fourth generation branched poly(amine-ester) (HPAE-OHs4). The chemical structures of copolymers were determined by FTIR, 1H-NMR, 13C-NMR, and TGA. Double emulsion (DE) and nanoprecipitation (NP) method were used to fabricate the nanoparticles of these copolymers encapsulating bovine serum albumin (BSA) as a model. DSC thermo-grams indicated that the nanoparticles with BSA kept stable below 40°C. Different factors which influence on particular size and encapsulation efficiency (EE) were investigated. Their EE to BSA could reach 97.8% at an available condition. In vitro release behavior of NPs showed a continuous release after a burst release. The stability maintenance of BSA in the nanoparticle release in vitro was also measured via circular dichroism and fluorescence spectrometry. The results showed that the copolymer nanoparticles have a promising potential in protein delivery system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010