title: NMR relaxation and magnetic properties of superparamagnetic nanoworms.
abstract: Maghemite particles are used as T₂ contrast agents for magnetic resonance imaging, especially for molecular and cellular imaging. Linear clusters of particles - called nanoworms - were recently developed to enhance the targeting efficiency. In this work, the magnetic and NMR relaxation properties of these nanoworms are studied at multiple magnetic fields. After the usual saturation at 0.5 T, the magnetization of the worms is still increasing, which results in an appreciable increase of the transverse relaxivity at high magnetic fields. The obtained relaxivities are typical of superparamagnetic particles of iron oxide (SPIOs). The transverse relaxation of the worms is clearly more efficient than for the isolated grains, which is confirmed by computer simulations. At high field, the longitudinal relaxation of the worms is less pronounced than for the grains, as expected for SPIOs. The nanoworms thus constitute a promising T₂ agent for cellular and molecular imaging.
authors.affiliation: Biological Physics Department, Université de Mons, Mons, Belgium. yves.gossuin@umons.ac.be
authors.forename: Yves
authors.initials: Y
authors.lastname: Gossuin
authors.forename: Sabrina
authors.initials: S
authors.lastname: Disch
authors.forename: Quoc L
authors.initials: QL
authors.lastname: Vuong
authors.forename: Pierre
authors.initials: P
authors.lastname: Gillis
authors.forename: Raphaël P
authors.initials: RP
authors.lastname: Hermann
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sailor
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D003911:Dextrans; D005290:Ferric Compounds; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D003911:Dextrans; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide