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.
A series of pH-responsive polymeric micelles is developed to act as intelligent carriers to deliver iron oxide (Fe(3)O(4)) 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 Fe(3)O(4) 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 Fe(3)O(4) nanoparticles. The Fe(3)O(4)-loaded polymeric micelle was measured by dynamic light scattering (DLS), superconducting quantum interference device (SQUID) and a 3.0T 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 Fe(3)O(4) 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.
Gao
Guang Hui
GH
Theranostic Macromolecules Research Center, Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon 440-746, South Korea.
Lee
Jae Won
JW
Nguyen
Minh Khanh
MK
Im
Geun Ho
GH
Yang
Jehoon
J
Heo
Hyejung
H
Jeon
Pyoung
P
Park
Tae Gwan
TG
Lee
Jung Hee
JH
Lee
Doo Sung
DS
D000818:Animals; D002545:Brain Ischemia / Q000175:diagnosis*; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry; D005290:Ferric Compounds / Q000008:administration & dosage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008823:Micelles; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003287:Contrast Media; D003692:Delayed-Action Preparations; D005290:Ferric Compounds; D008823:Micelles; D011108:Polymers; C507253:poly(beta-amino ester); C000499:ferric oxide; D011092:Polyethylene Glycols