title: A cancer-recognizable MRI contrast agents using pH-responsive polymeric micelle.
abstract: A cancer-recognizable MRI contrast agents (CR-CAs) has been developed using pH-responsive polymeric micelles. The CR-CAs with pH sensitivity were self-assembled based on well-defined amphiphilic block copolymers, consisting of methoxy poly(ethylene glycol)-b-poly(L-histidine) (PEG-p(L-His)) and methoxy poly(ethylene glycol)-b-poly(L-lactic acid)-diethylenetriaminopentaacetic acid dianhydride-gadolinium chelate (PEG-p(L-LA)-DTPA-Gd). The CR-CAs have a spherical shape with a uniform size of ~40 nm at physiological pH (pH 7.4). However, in acidic tumoral environment (pH 6.5), the CR-CAs were destabilized due to the protonation of the imidazole groups of p(L-His) blocks, causing them to break apart into positively charged water-soluble polymers. As a result, the CR-CAs exhibit highly effective T1 MR contrast enhancement in the tumor region, which enabled the detection of small tumors of ~3 mm(3 )in vivo at 1.5 T within a few minutes.
authors.affiliation: Department of Biotechnology, The Catholic University of Korea, 43 Jibong ro, Wonmi-gu, Bucheon-si, Gyeonggi do 420-743, Republic of Korea.
authors.forename: Kyoung Sub
authors.initials: KS
authors.lastname: Kim
authors.forename: Wooram
authors.initials: W
authors.lastname: Park
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: You Han
authors.initials: YH
authors.lastname: Bae
authors.forename: Kun
authors.initials: K
authors.lastname: Na
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003287:Contrast Media; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008823:Micelles; D018613:Microscopy, Confocal; D010316:Particle Size; D011108:Polymers
chemical_list: D003287:Contrast Media; D008823:Micelles; D011108:Polymers
keywords: Cancer diagnosis; Imaging agents; Magnetic resonance imaging; Micelles; pH-responsive materials