title: Preparation of magnetic iron oxide nanoparticles for hyperthermia of cancer in a FeCl₂-NaNO₃-NaOH aqueous system.
abstract: Magnetic iron oxide nanoparticles (MIONPs) were synthesized in a FeCl₂-NaNO₃-NaOH aqueous system under various initial Fe(2+)/NO⁻₃ molar ratios (α) and Fe(2+)/OH- molar ratios (β) in order to clarify the effects of the initial molar ratio of reactants on the reaction mechanism. The Fe(2+)/NO⁻₃ /OH(-) molar ratio of 3 : 1 : 5 led to the formation of magnetic nanoparticles mainly composed of magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃). The 36 nm sized γ-Fe₂O₃ and 413 nm sized Fe₃O₄ were obtained by changing the order in which NaNO₃ was added to a NaOH solution. The in vitro heat generations of the resulting MIONPs in an agar phantom were measured under an alternating magnetic field (100 kHz, 23.9 kA/m). The temperature rise (ΔT) of the agar phantom for the 36 nm sized γ-Fe₂O₃ was 55°C in the first 140 s, with a concentration of 58 mg Fe/mL. Our results showed that it is possible to prepare MIONPs with high heating efficiencies under optimal conditions using the present method.
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan. zhixia@ecei.tohoku.ac.jp
authors.forename: Zhixia
authors.initials: Z
authors.lastname: Li
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kawashita
authors.forename: Norio
authors.initials: N
authors.lastname: Araki
authors.forename: Michihide
authors.initials: M
authors.lastname: Mitsumori
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Doi
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry* / Q000627:therapeutic use; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000627:therapeutic use / Q000648:ultrastructure; D009369:Neoplasms / Q000628:therapy*; D010084:Oxidation-Reduction
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide