London, July 9 : US scientists have invented a handheld nuclear magnetic resonance (NMR) scanner that can facilitate the diagnoses of diseases and identification of pathogens.
Ralph Weissleder at Harvard Medical School in Cambridge, Massachusetts, has revealed that the revolutionary scanner is many times smaller than conventional NMR spectroscopy machines, which require huge magnets to create the powerful magnetic fields necessary to make them work.
Nuclear magnetic resonance spectroscopy works by using a powerful magnetic field to line up nuclei in a sample, and then by zapping them with radio waves that cause them to wobble.
The researchers say that the currents induced by such precessions in a nearby coil can be used to determine the chemical structure of the molecules that contain the nuclei.
Magnetic resonance imaging machines also use the same process to make non-invasive images of human bodies.
The new device, however, does not produce images.
Conventional NMR spectroscopy machines require powerful fields to line up individual nuclei.
Weissleder and his colleagues have, however, found that magnetic nanoparticles generate a much larger signal than single nuclei, and can thus be detected using the weaker fields from small permanent magnets.
The researchers say that their idea is to coat such nanoparticles with molecules that bind to specific biomolecules, or bacteria and viruses.
They say that the binding process causes the nanoparticles to clump together, producing a measurable change in the signal they produce.
According to them, this approach may help identify a large variety of biological targets.
Weissleder says that the prototype machine is 800 times more sensitive than standard NMR scanners.
"The biggest advantage is that we don't need sample preparation or purification steps," New Scientist magazine quoted Hakho Lee, lead author on the research, as saying in a report published in the journal Nature Medicine.
"This method could provide an easy and fast way to diagnose almost any kind of disease, such as bacterial infection or cancers in point-of-care settings - right next to the patient or in developing countries," the researcher adds.
The device may also help conduct water purity tests, and be applied to gaseous samples to search for airborne pathogens or pollutants.
Impressed with the work, Dusan Uhrin, an NMR spectroscopist at the University of Edinburgh, said: "If you came to my lab you would see that our spectrometers occupy whole rooms, and we are always struggling with sensitivity in NMR experiments."
He added: "They have been able to improve the sensitivity such that they can detect just a few bacteria. It's quite remarkable that they can detect down to that limit."
Weissleder has filed a patent for the design, and started a company called T2 Biosystems to market the devices.