title: Structural characterization of ultrasmall superparamagnetic iron oxide (USPIO) particles in aqueous suspension by energy dispersive X-ray diffraction (EDXD).
abstract: Ultrasmall superparamagnetic iron oxide (USPIO) particles were structurally characterized in situ in an aqueous dilute suspension by energy dispersive X-ray diffraction (EDXD) and ex situ as powders obtained by lyophilization of the suspension by angular dispersive X-ray diffraction (ADXD) at 20 degrees C. Structural parameters obtained by the Rietveld method on ADXD data were used as starting parameters for modeling the structure of the particles in suspension. Although each particle is a single crystal, as evidenced by conventional X-ray diffraction, our results indicate that the structural order, specific to a crystal, does not extend to the entire volume of the particle. In fact, each individual particle, averagely, has a crystalline structural extension ca. 4.0 nm smaller than the apparent dimensions obtained by both ADXD and TEM (ca. 8.0 nm).
authors.affiliation: Faculté de Pharmacie, Université de Paris Sud, UMR CNRS 8612, tour D5, 5 Rue JB Clément, 92926 Châtenay Malabry, France.
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Di Marco
authors.forename: Marc
authors.initials: M
authors.lastname: Port
authors.forename: Patrick
authors.initials: P
authors.lastname: Couvreur
authors.forename: Catherine
authors.initials: C
authors.lastname: Dubernet
authors.forename: Paolo
authors.initials: P
authors.lastname: Ballirano
authors.forename: Claudia
authors.initials: C
authors.lastname: Sadun
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry*; D053768:Metal Nanoparticles; D015394:Molecular Structure; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D014867:Water; C000499:ferric oxide