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.
"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, 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."
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," Lieber says, adding that the risk of false readings is minimized by the incorporation of various control nanowires.
The scientists also fitted some nanowires in the arrays with nucleic acid receptors for telomerase, an enzyme inactive in most of the body's somatic cells but active in at least 80 percent of known human cancers. In testing of extracts from as few as 10 tumour cells, these receptors allowed real-time monitoring of telomerase binding and activity.
COMPAMED.de; Source: Harvard University