Researchers at Cornell University and U.S. Military Academy are working hard on development of a method to detect the magnetic imbalance of nitroxides, stable organic compounds that have an unpaired electron. Nitroxides can be attached to other molecules, and so there’s a possibility to track just about anything at the nano level.
By creating a sample of nitroxide molecules dissolved in a thin-film polymer and bringing the sample close to a 4-micron nickel magnet attached to a 350-nanometer silicon cantilever, they can detect the electron spin by measuring the frequency of the cantilever as it wobbles, like a diving board. The cantilever is similar to those used in scanning probe microscopy, a type of imaging that involves a cantilever scanning a surface and recording the probe-surface interactions.
To improve their frequency readouts and get more accurate measurements, the group must learn, among others things, how to make their magnets smaller, Marohn said [John Marohn, associate professor of chemistry].
Full story at Cornell Chronicle: Researchers are on the path to creating nano-MRI images…
Abstract in PNAS: Scanned-probe detection of electron spin resonance from a nitroxide spin probe