Colloidal lithography was used to prepare patterns of Fe3O4 nanoparticles on a glass surface using basic steps of mixing, drying and removing the surface template of latex spheres. Monodisperse latex were used to guide the deposition of magnetic nanoparticles to collect in the spaces in between the close-packed spheres of the latex film. With a mixture approach of “two-particle” lithography, 2D arrays of patterned aggregates of metal nanoparticles were generated which formed a periodic, well-defined arrangement that was suitable for subsequent characterizations with magnetic sample modulation (MSM).

To perform a study, the person is positioned within an MRI scanner that forms a strong magnetic field around the area to be imaged. First, energy from an oscillating magnetic field is temporarily applied to the patient at the appropriate resonance frequency. Scanning with X and Y gradient coils causes a selected region of the patient to experience the exact magnetic field required for the energy to be absorbed. The atoms are excited by a radio frequency (RF) pulse and the resultant signal is measured by a receiving coil. The RF signal may be processed to deduce position information by looking at the changes in RF level and phase caused by varying the local magnetic field using gradient coils.