This technique is so sensitive that even when these cancer markers constitute only one hundred-billionth of the protein present in a drop of blood it is still detectable. 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 Dr Charles Lieber, professor of chemistry in Harvard. “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. 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.