title: Assessing the hyperthermic properties of magnetic heterostructures: the case of gold-iron oxide composites.
abstract: Gold-iron oxide composites were obtained byin situreduction of an Au(III) precursor by an organic reductant (either potassium citrate or tiopronin) in a dispersion of preformed iron oxide ultrasmall magnetic (USM) nanoparticles. X-ray diffraction, transmission electron microscopy, chemical analysis and mid-infrared spectroscopy show the successful deposition of gold domains on the preformed magnetic nanoparticles, and the occurrence of either citrate or tiopronin as surface coating. The potential of the USM@Au nanoheterostructures as heat mediators for therapy through magnetic fluid hyperthermia was determined by calorimetric measurements under sample irradiation by an alternating magnetic field with intensity and frequency within the safe values for biomedical use. The USM@Au composites showed to be active heat mediators for magnetic fluid hyperthermia, leading to a rapid increase in temperature under exposure to an alternating magnetic field even under the very mild experimental conditions adopted, and their potential was assessed by determining their specific absorption rate (SAR) and compared with the pure iron oxide nanoparticles. Calorimetric investigation of the synthesized nanostructures enabled us to point out the effect of different experimental conditions on the SAR value, which is to date the parameter used for the assessment of the hyperthermic efficiency.
authors.affiliation: INSTM and Department of Chemistry 'U. Schiff' , Università degli Studi di Firenze , Via della Lastruccia 3, 50019 Sesto Fiorentino (FI) , Italy.
authors.forename: Elvira
authors.initials: E
authors.lastname: Fantechi
authors.affiliation: INSTM and Department of Chemical and Geological Sciences, Università di Cagliari, 09042 Monserrato (CA), Italy; Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Seville, Spain; CABIMER-Andalusian Center for Molecular Biology and Regenerative Medicine, Seville, Spain.
authors.forename: Paula M
authors.initials: PM
authors.lastname: Castillo
authors.affiliation: INSTM and Department of Chemical and Geological Sciences , Università di Cagliari , 09042 Monserrato (CA) , Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Conca
authors.affiliation: INSTM and Department of Chemical and Geological Sciences , Università di Cagliari , 09042 Monserrato (CA) , Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cugia
authors.affiliation: INSTM and Department of Chemistry 'U. Schiff', Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy; CNR-ICCOM and INSTM, via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Sangregorio
authors.affiliation: INSTM and Department of Chemical and Geological Sciences , Università di Cagliari , 09042 Monserrato (CA) , Italy.
authors.forename: Maria Francesca
authors.identifier: 0000-0002-2973-0002
authors.initials: MF
authors.lastname: Casula
keywords: SAR; gold–iron oxide; magnetic hyperthermia; nanoheterostructures