Preparation and characterization of PNIPAAm-b-PLA/Fe3O4 thermo-responsive and magnetic composite micelles

Novel magnetic micelles with the flowerlike morphology were prepared with Fe3O4 nanoparticles and poly (N-isopropylacrylamide)-block-polylactide (PNIPAAm-b-PLA) copolymers by a dialysis method. The diameter of flowerlike micelles was about 1 mu m. The core and shell of the micelles were hydrophilic, while the other area of the micelles was hydrophobic. The lower critical solution temperature (LCST) of PNIPAAm-b-PLA was about 38 degrees C. The magnetic intensity of Fe3O4 nanoparticles decreased after they were encapsulated into PNIPAAm-b-PLA micelles. Thermo-responsive and magnetic properties of the micelles would provide useful applications in the target drug delivery and release system. (C) 2008 Elsevier B.V. All rights reserved.