title: Gadolinium-based hybrid nanoparticles as a positive MR contrast agent.
abstract: A new nanoparticulate inorganic-organic hybrid-type positive contrast agent (CA), PGP/dextran-K01, was synthesized based on a GdPO4 inorganic core as a relaxation-time-shortening moiety and a dextran-coating, which generates monodispersibility in water, a high relaxation-time-shortening effect by retaining a large number of water molecules in proximity of the core and toxicity reduction in in-vivo studies. This PGP/dextran-K01 nanoparticle has high r1 and r2 values and a significantly low r2/r1 value, 1.1, which is unprecedented and which is the lowest value among existing nanoparticulate CAs indicating that PGP/dextran-K01 is a positive contrast agent. Because of this low r2/r1 value and the nanoparticulate shape, PGP/dextran-K01 will be a useful clinical substitute for negative CAs based on iron oxides.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hifumi
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamaoka
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tanimoto
authors.forename: Daniel
authors.initials: D
authors.lastname: Citterio
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry*; D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D010710:Phosphates / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D003287:Contrast Media; D003911:Dextrans; D010710:Phosphates; D005682:Gadolinium