Functionalization of Fe3O4 nanoparticles

Abstract

Magnetic iron oxide (Fe₃O₄) nanoparticles are used as ferrofluids and in biomedical field as diagnostic and therapeutic tools, contrast agents in magnetic resonance imaging, drug delivery to tumor cells, cancer treatment by hyperthermia. These applications usually require uniform, chemically stable and monodispersed particles in liquid media. As a result of anisotropic dipolar attraction, nanoparticles of iron oxide aggregate into large clusters which may lead to the failure of their properties. Surface modification is often required to prevent such aggregation of nanoparticles. It has been already proved that aggregation can be avoided by surface modification of Fe₃O₄ nanoparticles using silica. The present work seeks the preparation and characterizations of monodispersed magnetic nanoparticles (Fe₃O₄) as well as silica coating. Fe₃O₄ nanoparticles have been synthesized using thermal decomposition route. The reaction involves high temperature (230 °C) heating of iron acetylacetonate Fe(acac)₃ in the presence of reducing agent and surfactant. Structural characterizations and surface chemistry of nanoparticles have been analyzed using X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy. Further work has been extended by coating as prepared Fe₃O₄ nanoparticles with silica. It reveals from microscopic analysis that each silica sphere contains several monodisperse Fe₃O₄ NP.