Say goodbye to your wimpy 3um MRI, as researchers from IBM’s Almaden Research Center are using a form of atomic force microscopy that uses the proton spins typically used in larger-scale MRI to reach down to the 90nm range. They call it magnetic resonance force microscopy (MRFM). John Mamin explains in detail…
“Our MRFM method measures a very tiny magnetic force between the nuclei in the sample and a nearby nanomagnet” John Mamin explains to Nanowerk. “Many types of common atoms, including hydrogen, fluorine, phosphorus, copper, aluminum, etc. have nuclei that are very weakly magnetic. Sometimes this basic magnetic property would be referred to as the nuclear ‘spin’. MRI typically uses the magnetism of hydrogen nuclei contained in water. In our work, we are using the magnetism of fluorine nuclei contained in a small sample of calcium fluoride, though we can also use hydrogen.”
MRFM uses a magnetic tip and an ultrasensitive cantilever to sense the magnetic force generated between the tip and spins in a sample. Unlike the permanent magnet tips previously used for MRFM detection of electron spin resonance, the tips used by the IBM researchers are based on a thin film of magnetic material that has a high magnetic moment, but is magnetically soft.
All this magic has direct imaging of protein structure in mind. It’d be pretty cool to “see” the structures that are usually inferred though other methods.
Curious what “magnetically soft” means? See the Nanowerk article or the published work in Nature Nanotechnology…