Researchers develop MRI for the nanoscale

Researchers have been able to shrink MRI technology to the nanoscale.

An international team off researchers from the University of Stuttgart and elsewhere are using tiny defects in diamonds to sense the magnetic resonance in molecules. Their research was reported this month in the journal Science.

The technique "brings MRI to a level comparable to an atomic force microscope, said Carlos Meriles, an associate professor of physics at the City College of New York, and one of the authors of the study, in an announcement. Standard MRI usually gets a resolution of 100 microns, Meriles said, which is about the width of a human hair, while nanoscale MRI would have a resolution 1,000 to 10,000 times better.

To pick up magnetic resonance on such a small scale the researchers took advantage of the spin of protons in an atom, specifically that of a diamond. Diamonds are made up almost entirely of carbon atoms, but when a nitrogen atom moves into a spot where a carbon atom is missing, it creates an imperfection called a nitrogen-vacancy (NV) center.

"These imperfections turn out to have a spin--like a little compass--and have some remarkable properties," Meriles said. They can, for example, serve as sensors and pick up the magnetic resonance of single organic cells, he added.

"If you can see on single molecule scale what is going on, and understand more details about what is happening, you may be able to find exactly what the problem is and target it specifically," Philip Hemmer, a professor of electrical and computer engineering at Texas A&M University, said in an article in the MIT Technology Review. Hemmer wrote a perspective on the study in the same issue of Science.

"Ultimately," Meriles said, "one will use a nitrogen-vacancy mounted on the tip of an atomic force microscope--or an array of NVs distributed on the diamond surface--to allow a scanning view of a cell, for example, to probe nuclear spins with a resolution down to a nanometer or perhaps better."

To learn more:
- read the study abstract
- see the announcement
- read the article in MIT Technology Review
- see the perspective on the study in Science