Micromagnets for multispectral magnetic resonance imaging

New optical bio-imaging techniques are behind much of the recent growth in molecular and cellular biology research. Many of these imaging advances are due to the introduction of new coloured fluorophores such as fluorescent proteins and quantum dots. Used as biological tags/labels, their distinct colours enable simultaneous tracking of multiple biological indicators. Unfortunately, equivalent multiplexing capabilities are largely absent in magnetic resonance imaging (MRI). Corresponding MRI labels have generally been limited to chemically synthesized paramagnetic molecules and superparamagnetic nano- and microparticles that are substantially indistinguishable from one another. This talk introduces a top-down microfabrication approach to MRI contrast agent engineering that enables encoding of distinct spectral signatures into the geometry of magnetic microstructures. Although based on different principles to those of optically-probed nanoparticles, these new magnetic microstructures permit a multiplexing functionality in the magnetic resonance radio-frequency (RF) spectrum that is in many ways analogous to that permitted by quantum dots in the optical spectrum. Additionally, in situ modification of particle geometries may facilitate RF probing of various local physiological variables. The talk will be aimed at an introductory level and will not assume any prior biology or MRI knowledge.