In the June 23rd issue of Proceedings of the National Academy of Science, scientists described their cancer-detecting electric nose. It can process sample cells and sniff out harmful ones, the same way a human nose uses selective receptors to detect certain smells.

The chemical nose includes three such receptors now, but the researchers have hundreds more that they can add to the array, making the chemical nose more and more useful.

What makes this technology so powerful is its ability to adapt. When the human nose detects a new smell, the brain records the new smell and can remember previously experienced smells. The same is true of the chemical nose: it can cross-reference everything it detects with an extensive memory of cancer markers, creating new patterns when it needs to.

The result is an adaptable, precise method for cataloging and detecting new markers for various types of cancer. And just as a human nose can tell when something is "off," the chemical nose can also signal any abnormality, even if it can't pinpoint precisely what the problem is.

Now that this chemical nose can sniff cancer, maybe we can give the cancer sniffing cat a break.

'Chemical Nose' May Sniff Out Cancer Earlier [via Science Daily]

For further reading: What's the Future of Cancer Diagnosis?

(Image: an illustration of the chemical nose receptors at work, from University of Massachusetts Amherst)

Here's what's happening inside that metal box. Inventor Joel White created the ScenTrak for his company Cogniscent, and has just published an article about how it works in PLoS Biology. He and his co-authors write:

Biological systems can provide engineering guidance on how evolution has solved particular problems. In the context of detecting chemicals in either the aqueous or vapor phase, two general biological approaches have emerged. The first relies on individual highly specific single receptors (sensors), each tuned to detect a single molecular species—examples include the receptors that mediate pheromone detection in insects or those that function in neurotransmission. Specificity is achieved by narrow band design. The second approach is implemented by arrays of receptors with relatively broad responses. In this case, specificity emerges from a constellation of receptor types that recognizes the molecule of interest—the canonical example here is the olfactory receptors in the main olfactory system of vertebrates. Specificity is achieved by a "one chemical-many broadly responsive detectors" paradigm. While trying to mimic the enormous odor coding ability of biological olfaction in an "artificial nose," we searched for molecules with the requisite combinatorial capacity to serve as odor detectors. Here we show that single-stranded DNA molecules tagged with a fluorescent reporter and deposited onto solid surfaces can respond to vapor phase odor pulses in a sequence-selective manner.

DNA Detects Volatile Compounds in Vapor Phase [PLoS Biology]