Synthesis of Fe3O4 magnetic fluid used for magnetic resonance imaging and hyperthermia

Fe3O4 magnetic nanoparticles were prepared by co-precipitation from FeSO4 center dot 7H(2)O and FeCl3 center dot 6H(2)O aqueous solutions using NaOH as precipitating reagent. The nanoparticles have an average size of 12 nm and exhibit superparamagnetism at room temperature. The nanoparticles were used to prepare a water-based magnetic fluid using oleic acid and Tween 80 as surfactants. The stability and magnetic properties of the magnetic fluid were characterized by Gouy magnetic balance. The experimental results imply that the hydrophilic block of Tween 80 can make the Fe3O4 nanoparticles suspending in water stable even after dilution and autoclaving. The magnetic fluid demonstrates excellent stability and fast magneto-temperature response, which can be used both in magnetic resonance imaging and magnetic fluid hyperthermia. (C) 2011 Elsevier B.V. All rights reserved.