Posted on 10/25/2007 4:18:00 PM PDT by neverdem
Mini-explosions under a cell sample could help to identify disease.
Mass spectrometry on single cells could tell if they are cancerous or diseased.SCIENCE SOURCE/SPLAn explosive chemical technique can now be used to identify individual molecules in biological samples, down to the single-cell level.
Researchers hope the procedure could be used in clinics a few years from now to screen blood or urine for metabolites — the final products of biological processes — that can be used to diagnose disease.
"The vast majority of small molecules in humans are unknown," says Gary Siuzdak at the Scripps Center for Mass Spectrometry, La Jolla, California. "People don't appreciate this." But his technique could change that: "The potential for diagnosing and understanding disease is really wonderful," he says.
The mass-spectrometry technique developed by Siuzdak and colleagues, known as nanostructure-initiator mass spectrometry (NIMS), is reported in Nature 1 this week.
The process relies on a slab of silicon etched with nanometre-sized holes filled with 'initiator' molecules. The sample sits on top of this layer. The uneven surface is then hit with an ionising beam, or a laser, at which point the molecules trapped in the nanoholes heat up until they explode outwards into the sample. This pushes molecules off the sample surface as gaseous ions, which can be detected and identified by the mass spectrometer.
Strong but gentle The technique offers a number of advantages over others, Siuzdak says. Although the exploding initiator molecules are "pretty forceful", in some ways they are relatively gentle: because the sample is ionised by exploding particles — rather than being directly hit with an ion beam or a laser — surface molecules are released whole rather than being shattered into fragments.
And because the sample doesn't need to be mixed with anything, it is easier to identify the molecules...
(Excerpt) Read more at nature.com ...
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