A diamond surface containing nitrogen–vacancy defects (dark spots) can detect molecules on the nanoscale. IBM RESEARCH


Diamond defects shrink MRI to the nanoscale

Technique could be sensitive enough to detect structure of a single protein.

Katharine Sanderson
31 January 2013

Diamond-based quantum devices can now make nuclear magnetic resonance measurements on the molecular scale. Work by two independent groups will make it easier to find out the structure of single biological molecules such as proteins without destroying or freezing them.

Nuclear magnetic resonance (NMR) and its close cousin magnetic resonance imaging (MRI) give information about a sample’s structure by detecting the weak magnetic forces in certain atomic nuclei, such as hydrogen. They work by detecting how molecules collectively resonate — like guitar strings that vibrate together — with electromagnetic waves of specific wavelengths. The techniques provide information about the structure of samples without damaging them — which is particularly important if the sample is a human body.

But to some researchers, whole bodies are less interesting than the molecules that they are made up of. “I want to push NMR and MRI to the molecular level,” says Friedemann Reinhard, a physicist at the University of Stuttgart in Germany. His team is one of two that have used NMR to detect hydrogen atoms in samples measuring just a few nanometres across1. The second team2 was led by Daniel Rugar, manager of nanoscale studies at IBM’s Almaden Research Center in San Jose, California. Both studies are published in this week’s Science.

Read more: Diamond defects shrink MRI to the nanoscale : Nature News & Comment.

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