11. pH-responsive polymeric micelle based on PEG-poly(β-amino ester)/(amido amine) as intelligent vehicle for magnetic resonance imaging in detection of cerebral ischemic area
作者：Guang Hui Gao , Jae Won Lee , Minh Khanh Nguyen , Geun Ho Im , Jehoon Yang , Hyejung He
關鍵字：pH-responsive Polymeric micelle Iron oxide nanoparticles Contrast agent Magnetic resonance imaging
論文來源：期刊
具體來源：Journal of Controlled Release
發表時間：2011年
A series of pH-responsive polymeric micelles is developed to act as intelligent carriers to deliver iron oxide
(Fe3O4) nanoparticles and respond rapidly to an acidic stimuli environment for magnetic resonance imaging
(MRI). The polymeric micelle can be self-assembled at physiological pH by a block copolymer, consisting of a
hydrophilic methoxy poly(ethylene glycol) (PEG) and a pH-responsive poly(β-amino ester)/(amido amine)
block. Consequently, the Fe3O4 nanoparticles can be well encapsulated into polymeric micelles due to the
hydrophobic interaction, shielded by a PEG coronal shell. In an acidic environment, however, the pH-
responsive component, which has ionizable tert-amino groups on its backbone, can become protonated to be
soluble and release the hydrophobic Fe3O4 nanoparticles. The Fe3O4-loaded polymeric micelle was measured
by dynamic light scattering (DLS), superconducting quantum interference device (SQUID) and a 3.0 T MRI
scanner. To assess the ability of this MRI probe as a pH-triggered agent, we utilize a disease rat model of
cerebral ischemia that produces acidic tissue due to its pathologic condition. We found gradual accumulation
of Fe3O4 nanoparticles in the brain ischemic area, indicating that the pH-triggered MRI probe may be effective
for targeting the acidic environment and diagnostic imaging of pathologic tissue.