作者：Weizhong Yuan, Jinying Yuan*, Lilin Zhou, Sizhu Wu, Xiaoyin Hong
关键字：Superparamagnetic nanoparticles,Brush polymeric shell,Degradation
论文来源：期刊
具体来源：Polymer, 2010, 51(12), 2540-2547
发表时间：2010年

Well-defined monodisperse Fe₃O₄@poly (2-hydroxyethyl methacrylate)-graft- poly(e-caprolactone)( Fe₃O₄@PHEMA-g-PCL) magnetic nanoparticles with novel topological structure, i.e., with branched brush polymeric shell, were successfully prepared by the combination of atom transfer radical polymerization(ATRP) and ring-opening polymerization (ROP). Oleic acid stabilized monodisperse Fe3O4
nanoparticles were prepared by a convenient organic phase process and underwent a ligand exchange process with 2-bromo-2-methylpropionic acid (Br-MPA) to generate macroinitiator ( Fe₃O₄@Br-MPA) for ATRP of 2-hydroxyethyl methacrylate (HEMA) to produce  Fe₃O₄@poly(2-hydroxyethyl methacrylate)
( Fe₃O₄@PHEMA). PCL segments were grafted from the side of PHEMA by the ROP of e-caprolactone (CL) with the hydroxyl groups of PHEMA segments used as initiation centers, and then  Fe₃O₄@PHEMA-g-PCL magnetic nanoparticles were obtained. PCL segments of  Fe₃O₄@PHEMA-g-PCL possessed lower degree of
crystallinity than that of linear PCL. Meanwhile,  Fe₃O₄@PHEMA-g-PCL nanoparticles showed superparamagnetism and comparatively strong magnetization. In vitro degradation investigation indicated that the degradation rate of PCL segments in  Fe₃O₄@PHEMA-g-PCL increased with the decrease of the
length of PCL chains. The release behavior of model drug chlorambucil from the nanoparticles indicated that the rate of drug release could be adjusted by altering the chain-length of PCL segments