title: Gadolinium containing photochromic micelles as potential magnetic resonance imaging traceable drug carriers.
abstract: Novel photochromic amphipathic molecules, KMR-AZn (Gd-DTPA-AZCn), composed of hydrophilic Gd-DTPA and hydrophobic alkylated azobenzene were prepared. In aqueous environment, KMR-AZn indicated self-assembly. The resulting aggregates were demonstrated to be able to include a hydrophobic drug substitute (hydrophobic fluorescent dye) into the internal core, and to release the included compound upon photoirradiation within 10 min through the influence of azobenzene photoisomerization. This micellar MRI contrast agent exhibited three- to four-fold higher r(1) relaxivity (r(1) = 14.5-16.5 mM(-1) s(-1), 0.47 T at 40°C) than the widely applied small molecule contrast agent Gd-DTPA (Magnevist(®) r(1)  = 4.1 mM(-1) s(-1), 0.47 T at 40°C). This dual functionality of encapsulated compound release and increased MR imaging contrast indicates that KMR-AZn is a potential candidate for application as a lipid-based MRI-traceable drug carrier.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Heta
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kumaki
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hifumi
authors.forename: Daniel
authors.initials: D
authors.lastname: Citterio
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tanimoto
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D003287:Contrast Media / Q000138:chemical synthesis*; D004337:Drug Carriers / Q000138:chemical synthesis*; D005682:Gadolinium / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000031:analogs & derivatives* / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008027:Light; D008279:Magnetic Resonance Imaging / Q000379:methods; D008823:Micelles; D010078:Oxazines; D055668:Photochemical Processes; D013501:Surface-Active Agents / Q000138:chemical synthesis*; D014867:Water
chemical_list: D001391:Azo Compounds; D003287:Contrast Media; D004337:Drug Carriers; D008823:Micelles; D010078:Oxazines; D013501:Surface-Active Agents; D014867:Water; D005682:Gadolinium; D019786:Gadolinium DTPA; C044808:nile red