title: Polyethylene Glycol-Mediated Synthesis of Cubic Iron Oxide Nanoparticles with High Heating Power.
abstract: Iron oxide magnetic nanoparticles (IOMNPs) have been successfully synthesized by means of solvothermal reduction method employing polyethylene glycol (PEG200) as a solvent. The as-synthesized IOMNPs are poly-dispersed, highly crystalline, and exhibit a cubic shape. The size of IOMNPs is strongly dependent on the reaction time and the ration between the amount of magnetic precursor and PEG200 used in the synthesis method. At low magnetic precursor/PEG200 ratio, the cubic IOMNPs coexist with polyhedral IOMNPs. The structure and morphology of the IOMNPs were thoroughly investigated by using a wide range of techniques: TEM, XRD, XPS, FTIR, and RAMAN. XPS analysis showed that the IOMNPs comprise a crystalline magnetite core bearing on the outer surface functional groups from PEG200 and acetate. The presence of physisorbed PEG200 on the IOMNP surface is faintly detected through FT-IR spectroscopy. The surface of IOMNPs undergoes oxidation into maghemite as proven by RAMAN spectroscopy and the occurrence of satellite peaks in the Fe2p XP spectra. The magnetic studies performed on powder show that the blocking temperature (TB) of IOMNPs is around 300 K displaying a coercive field in between 160 and 170 Oe. Below the TB, the field-cooled (FC) curves turn concave and describe a plateau indicating that strong magnetic dipole-dipole interactions are manifested in between IOMNPs. The specific absorption rate (SAR) values increase with decreasing nanoparticle concentrations for the IOMNPs dispersed in water. The SAR dependence on the applied magnetic field, studied up to magnetic field amplitude of 60 kA/m, presents a sigmoid shape with saturation values up to 1700 W/g. By dispersing the IOMNPs in PEG600 (liquid) and PEG1000 (solid), it was found that the SAR values decrease by 50 or 75 %, indicating that the Brownian friction within the solvent was the main contributor to the heating power of IOMNPs.
authors.affiliation: Department of Pharmaceutical Physics-Biophysics, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, Pasteur 6, 400349, Cluj-Napoca, Romania. cristian.iacovita@umfcluj.ro.
authors.forename: Cristian
authors.initials: C
authors.lastname: Iacovita
authors.affiliation: Department of Pharmaceutical Physics-Biophysics, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, Pasteur 6, 400349, Cluj-Napoca, Romania. rares.stiufiuc@umfcluj.ro.
authors.forename: Rares
authors.initials: R
authors.lastname: Stiufiuc
authors.affiliation: Interdisciplinary Research Institute on Bio-Nano-Science, Treboniu Laurian 42, 400271, Cluj-Napoca, Romania. teodora.radu@phys.ubbcluj.ro.|National Institute of Research and Development for Isotopic and Molecular Technologies, Donath 65-103, 400293, Cluj-Napoca, Romania. teodora.radu@phys.ubbcluj.ro.
authors.forename: Teodora
authors.initials: T
authors.lastname: Radu
authors.affiliation: Department of Cell and Molecular Biology, Faculty of Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Pasteur 6, 400349, Cluj-Napoca, Romania. aflorea@umfcluj.ro.
authors.forename: Adrian
authors.initials: A
authors.lastname: Florea
authors.affiliation: Faculty of Physics, "Babes Bolyai" University, Kogalniceanu 1, 400084, Cluj-Napoca, Romania. gabi.stiufiuc@phys.ubbcluj.ro.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Stiufiuc
authors.affiliation: Department of Physiology, Faculty of Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Clinicilor 1, 400006, Cluj-Napoca, Romania. alinagabriela.dutu@yahoo.com.
authors.forename: Alina
authors.initials: A
authors.lastname: Dutu
authors.affiliation: Faculty of Physics, "Babes Bolyai" University, Kogalniceanu 1, 400084, Cluj-Napoca, Romania. sever.mican@ubbcluj.ro.
authors.forename: Sever
authors.initials: S
authors.lastname: Mican
authors.affiliation: Faculty of Physics, "Babes Bolyai" University, Kogalniceanu 1, 400084, Cluj-Napoca, Romania. romulus.tetean@phys.ubbcluj.ro.
authors.forename: Romulus
authors.initials: R
authors.lastname: Tetean
authors.affiliation: Department of Pharmaceutical Physics-Biophysics, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, Pasteur 6, 400349, Cluj-Napoca, Romania. clucaciu@umfcluj.ro.
authors.forename: Constantin M
authors.initials: CM
authors.lastname: Lucaciu
keywords: Brownian friction; Cubic iron oxide magnetic nanoparticles; Dipole-dipole interactions; Magnetic hyperthermia; Polyethylene glycol; Specific absorption rate