title: Structural and magnetic characterization of superparamagnetic iron platinum nanoparticle contrast agents for magnetic resonance imaging.
abstract: The authors report the synthesis, from simple salts, and the physical characterization of superparamagnetic iron platinum nanoparticles (SIPPs) suitable for use as contrast agents in magnetic resonance imaging. The properties of these particles were determined by means of transmission electron microscopy (TEM), thermogravimetric analysis, inductively coupled plasma-optical emission spectroscopy (ICP-OES), superconducting quantum interference device (SQUID) magnetometry, and nuclear magnetic resonance relaxivity at 4.7 T. TEM showed that the diameters of the particles ranged from 9.3 to 10 nm, depending on the mole ratio of iron to platinum precursors, and on the concentration of octadecylamine (ODA) used in their preparation. The iron to platinum stoichiometry determined by ICP-OES varied from 1.4:1 to 3.7:1 and was similarly dependent on the initial mole ratios of iron and platinum salts, as well as on the concentration of ODA in the reaction. SQUID magnetometry showed that the SIPPs were superparamagnetic and had magnetic moments that increased with increasing iron content from 62 to 72 A·m2/kg Fe. The measured relaxivities of the SIPPs at 4.7 T were higher than commercially available superparamagnetic iron oxide nanoparticles, suggesting that these particles may be superior contrast agents in T2-weighted magnetic resonance imaging.
authors.affiliation: University of New Mexico, Department of Biochemistry and Molecular Biology, MSC08 4670, 1 University of New Mexico, Albuquerque, New Mexico 87131 and New Mexico Cancer Nanoscience and Microsystems Training Center , Albuquerque, New Mexico 87106.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Taylor
authors.affiliation: Sandia National Laboratories, Center for Integrated Nanotechnologies , P.O. Box 5800 MS 1304, Albuquerque, New Mexico 87111-1304.
authors.forename: Dale L
authors.initials: DL
authors.lastname: Huber
authors.affiliation: Sandia National Laboratories , Nanomaterials Sciences Department, Albuquerque, New Mexico 87185-1415.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Monson
authors.affiliation: nanoMR, Inc. , 2305 Renard Place SE, Suite 110, Albuquerque, New Mexico 87106.
authors.forename: Victor
authors.initials: V
authors.lastname: Esch
authors.affiliation: University of New Mexico, Department of Biochemistry and Molecular Biology, MSC08 4670, 1 University of New Mexico, Albuquerque, New Mexico 87131 and UNM Cancer Center , 1201 Camino de Salud NE, Albuquerque, New Mexico 87106.
authors.forename: Laurel O
authors.initials: LO
authors.lastname: Sillerud
keywords: iron oxide; iron platinum; superparamagnetic