Diagnostic Nose

Doctors and other healthcare providers rely heavily on their sense of smell when assessing a patient’s condition. For example, diabetes presents as a fruity smell on the breath, while foul odors are indicative of respiratory infections. But many compounds that are associated with diseases cannot be detected by the human nose, so Israeli chemical engineers have come up with a device that can do it automatically. Unlike other diagnostic “breathalyzers” that are disease-specific, the new device is capable of detecting multiple compounds in varying concentrations to identify a variety of disorders.

The prototype consists of an array of carbon nanotubes and gold particles, each covered with one of twenty organic films. Each film is sensitive to one of several compounds known to be present in the breath of people suffering from a range of illnesses including Parkinson’s disease, multiple sclerosis, bladder cancer and Crohn’s disease. When exposed to its specific compound, the electrical resistance of each film changes in a predictable manner, and the combined changes generate an electrical fingerprint that can be mapped to one of many different diseases.

The device was tested on 1,404 patients known to be suffering from at least one of the diseases being studied. A total of 2,808 samples were taken, and the results were varied but promising with an overall accuracy of 86 percent — more than adequate to warrant further refinement and additional studies.