title: 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.
abstract: 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.
authors.affiliation: Theranostic Macromolecules Research Center, Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Guang Hui
authors.initials: GH
authors.lastname: Gao
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Minh Khanh
authors.initials: MK
authors.lastname: Nguyen
authors.forename: Geun Ho
authors.initials: GH
authors.lastname: Im
authors.forename: Jehoon
authors.initials: J
authors.lastname: Yang
authors.forename: Hyejung
authors.initials: H
authors.lastname: Heo
authors.forename: Pyoung
authors.initials: P
authors.lastname: Jeon
authors.forename: Tae Gwan
authors.initials: TG
authors.lastname: Park
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Doo Sung
authors.initials: DS
authors.lastname: Lee
mesh_terms: 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
chemical_list: 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