Comparative Study of the Magnetic Behavior of Spherical and Cubic Superparamagnetic Iron Oxide Nanoparticles

A modified method for the production of cubic and spherical superparamagnetic nanoparticles is presented. Cubic nanoparticles can be made that are highly monodisperse down to a diameter of 8 nm. A detailed study is presented of the physical properties of these nanoparticles using high-resolution transmission electron microscopy analysis, X-ray powder diffraction, superconducting quantum interference device measurements, and relaxivity measurements performed in a magnetic resonance imaging scanner. It is found that cubic iron oxide nanoparticles have a higher degree of crystallinity and relaxivity (four times higher) than their spherical counterparts. These novel cubic iron oxide nanoparticles show great promise for use in biomedical imaging applications.