NMR advance could lead to tabletop devices

May 16, 2007 20:06 GMT  ·  By
900MHz, 21.2 T NMR Magnet at HWB-NMR, Birmingham, UK being loaded with a sample
   900MHz, 21.2 T NMR Magnet at HWB-NMR, Birmingham, UK being loaded with a sample

A new radical approach to nuclear magnetic resonance (NMR) uses a microscopic detector to severely decrease the amount of proteins required to measure molecular structures and could eventually produce a dramatic decrease in size of the existing devices.

Nuclear magnetic resonance (NMR) is a physical phenomenon based upon the quantum mechanical magnetic properties of an atom's nucleus that studies magnetic nuclei by aligning them with a very powerful external magnetic field and perturbing this alignment using an electromagnetic field.

Current NMR machines cost about $1 million and are the size of a massive SUV. They require large amounts of proteins to effectively detect their molecular structure and are used research laboratories and medical offices.

An MIT research team led by Yael Maguire, a former MIT graduate student who earned his Ph.D. for this work, developed a new imaging technique that not only needs less amounts of proteins for the studies, but could ultimately lead to the proliferation of tabletop NMR devices.

"It's revolutionary," said Shuguang Zhang, one of the authors and associate director of MIT's Center for Biological Engineering. "It's not just incremental progress."

Unlike today's techniques, that require a million billion molecules and tiny coils to study smaller samples, a scaling that has proven extremely difficult, the new device greatly decreases the number of molecules but is still able to perform the same analysis and it's only about one-third the size of a credit card.

The device uses technology similar to the Wi-Fi antennas found in laptop computers, consisting of flat strip of metal. With the help of a laser, the MIT team made a microscopic defect (a slot) in such a conducting structure, known as a strip line. In that location a little bit of the magnetic field leaks out of the line, creating a uniform, concentrated magnetic field. That field allows the slot to be used as an NMR probe, in place of a coil.

"The new technology could dramatically improve the rate of biomedical research applications, because it can take up to a year to obtain enough material for an NMR study using the coil probes", said co-author Professor Neil Gershenfeld, director of MIT's Center for Bits and Atoms.