title: Relaxometric and magnetic characterization of ultrasmall iron oxide nanoparticles with high magnetization. Evaluation as potential T1 magnetic resonance imaging contrast agents for molecular imaging.
abstract: Here we report on the synthesis of ultrasmall gamma-Fe2O3 nanoparticles (5 nm) presenting a very narrow particle size distribution and an exceptionally high saturation magnetization. The synthesis has been carried out by decomposition of an iron organometallic precursor in an organic medium. The particles were subsequently stabilized in an aqueous solution at physiological pH, and the colloidal dispersions have been thoroughly characterized by complementary techniques. Particular attention has been given to the assessment of the mean particle size by transmission electron microscopy, X-ray diffraction, dynamic light scattering, magnetic, and relaxometric measurements. The good agreement found between the different techniques points to a very narrow particle size distribution. Regarding the magnetic properties, the particles are superparamagnetic at room temperature and present an unusually high saturation magnetization value. In addition, we describe the potential of these particles as specific positive contrast agents for magnetic resonance molecular imaging.
authors.affiliation: Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Esfera de la UAB, 08193 Bellaterra, Catalunya, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Taboada
authors.forename: Elisenda
authors.initials: E
authors.lastname: Rodríguez
authors.forename: Anna
authors.initials: A
authors.lastname: Roig
authors.forename: Judit
authors.initials: J
authors.lastname: Oró
authors.forename: Alain
authors.initials: A
authors.lastname: Roch
authors.forename: Robert N
authors.initials: RN
authors.lastname: Muller
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D003287:Contrast Media / Q000494:pharmacology*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008027:Light; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010087:Oxides / Q000737:chemistry; D012542:Scattering, Radiation; D013696:Temperature; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; D014867:Water; C000499:ferric oxide