Published online by Cambridge University Press: 13 November 2013
New instrumentation is being developed to better understand the in vivo properties of magnetic particles suspended in solution or lodged in tissue. We describe three novel methods with the necessary sensitivity to measure the microscopic magnetic properties of individual magnetic particles and complexes quantitatively. The first method is based on proton nuclear magnetic resonance of a magnetic particle suspended in water in a microcapillary probe; the second method uses high-resolution magnetic resonance imaging of water surrounding a magnetic particle; and the third method is based on AC susceptometry with a magnetic cantilever that combines magnetic particle imaging concepts with probe microscopy. We present the physical basis for the measurements, estimate sensitivity limits, and discuss future impacts on the development of magnetic particles for bioimaging and bioassays.