%0 Journal Article
%T Synthesis and Evaluation of Magnetic Nanoparticles for Biomedical Applications
%A Nydeia W. Bolden
%A Vijaya K. Rangari
%A Shaik Jeelani
%A Seyhan Boyoglu
%A Shree R. Singh
%J Journal of Nanoparticles
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/370812
%X In this study, iron oxide (IO) nanoparticles from various precursors have been synthesized using sonochemical method and characterized for their structural variability and toxicity. The iron oxide (IO) precursor solutions were prepared from iron acetate (IA), iron pentacarbonyl (IP), decalin, PEG (poly(ethylene glycol)), EG (ethylene glycol), PVA (poly(vinyl alcohol)), ¦Â-cyclodextrin (CD), and distilled water. These precursor solutions were irradiated with high power ultrasound for 3 hours and heat treated as needed. These as-prepared iron oxide nanoparticles were characterized using X-ray diffraction (XRD), M£¿ssbauer spectroscopy, transmission electron microscopy (TEM), and magnetization measurements. XRD results show that all the particles are highly crystalline in nature and the particles sizes measured from TEM are approximately 5¨C20£¿nm. The maximum magnetization was observed for IO-IP at approximately 60.17£¿emu/g and the minimum was approximately 30.56£¿emu/g for IO-IA. These results confirm that the particles are superparamagnetic (SPM) in nature. M£¿ssbauer spectroscopy verified the magnetic nanoparticles are purely Fe3O4 and particles sizes varied by the nature of the precursor and coatings. 1. Introduction Iron based nanomaterials have found applications in many areas of science and technology due to their unique magnetic properties [1¨C5]. Recently, they are also used in biomedical applications such as MRI contrast agents for imaging [6], magnetic hyperthermia [7], and targeted drug delivery [8] because of their size compatibility [9] to cells, genes, and viruses. A size reduction of these materials from bulk to the nanoscale permits them to display various size related properties. Among other changes, a significant decrease in size can alter reactivity, increase surface area, and change the magnetic properties [10¨C12]. Iron oxide, for example, exhibits ferromagnetic behavior in bulk where it can reach full magnetization and the effect persists even after removal of the magnetic field. These same particles below a certain size (<20£¿nm) may exhibit a behavior similar to paramagnetism even when at temperatures below the Curie point. This is a nanoscale phenomenon, where the energy required to change the direction of the magnetic moment of a particle is comparable to the ambient thermal energy. The energy required to change the direction of magnetization of a crystallite is called the crystalline anisotropy energy and depends both on the material properties and the crystallite size. As the crystallite size decreases, so does the crystalline
%U http://www.hindawi.com/journals/jnp/2013/370812/