( Use of minuscule devices to spot cancer...)Nanowires can detect molecular signs of cancer, scientists find

Harvard University researchers have found that molecular markers indicating the presence of cancer in the body are readily detected in blood scanned by special arrays of silicon nanowires -- even when these cancer markers constitute only one hundred-billionth of the protein present in a drop of blood. In addition to this exceptional accuracy and sensitivity, the minuscule devices also promise to pinpoint the exact type of cancer present with a speed not currently available to clinicians.

A paper describing the work will appear in October in the journal Nature Biotechnology and is now posted on the journal's web site.

"This is one of the first applications of nanotechnology to healthcare and offers a clinical technique that is significantly better than what exists today," says author Charles M. Lieber, Mark Hyman Jr. Professor of Chemistry in Harvard's Faculty of Arts and Sciences. "A nanowire array can test a mere pinprick of blood in just minutes, providing a nearly instantaneous scan for many different cancer markers. It's a device that could open up substantial new possibilities in the diagnosis of cancer and other complex diseases."

Lieber and his colleagues linked slender nanowires conducting a small current with antibody receptors for certain cancer markers -- such as prostate specific antigen (PSA), PSA-a1-antichymotrypsin, carcinoembryonic antigen and mucin-1. When these telltale proteins come into contact with a receptor, it sparks a momentary change in conductance that gives a clear indication of the marker's presence. The detectors differentiate among various cancer markers both through the specific receptors used to snag them and because each binds its receptor for a characteristic length of time before dislodging.

"Our results show that these devices are able to distinguish among molecules with near-perfect selectivity," L
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Source:Harvard University