Nanowires detect cancer molecules

Atomic configurations of silicon nanowires created through assembly of silicon clusters, and connected to aluminum electrodes.

Could pinpoint type of cancer even with just one hundred-billionth of the protein in a drop of blood Molecular markers indicating cancer in the body can be detected by arrays of silicon nanowires, according to Harvard University researchers. The researchers say that the special nanowires can even detect cancer markers when they constitute just one hundred-billionth of the protein in a drop of blood.

Reporting in the journal Nature Biotechnology (read abstract), the researchers say that the nanowires could also pinpoint the type of cancer present with a speed not currently available.

"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 researcher Charles Lieber. "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."

According to a Harvard news release:

Lieber and 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 tumor cells, these receptors allowed real-time monitoring of telomerase binding and activity.

source: morover