Credit: © 2008 ACS

Breath analysis, which links specific volatile organic compounds (VOCs) in the breath to medical conditions, is advantageous because it is non-invasive, permits fast real-time monitoring and is less complicated than testing urine samples. Different approaches, such as gas-chromatography/mass-spectrometry (GC/MS) that separates and identifies the VOCs, have been used to detect lung cancer by analysing patients' breath. Researchers at the Israel Institute of Technology have now developed an array of sensors based on carbon nanotubes that differentiate VOCs in simulated healthy and cancerous breath samples.

Hossam Haick and colleagues1 first identified 15 biomarkers of lung cancer in the breath of patients using GC/MS, and used five representatives of these to simulate cancerous breath. They then created the sensor by depositing single-walled carbon nanotubes and palladium electrodes on a silicon wafer, before coating the wafer with various non-polymeric organic compounds that the biomarkers in the simulated breath will interact with to produce a measurable fingerprint. The diverse set of organic compounds permits a wide variety of biomarkers to be identified and increases the sensitivity of the device as well as its ability to discriminate closely related species. The sensor response was rapid and showed satisfactory signal-to-noise ratio at biomarker concentrations of between 10 parts per billion and 100 parts per million.

The authors suggest that the results could lead to the development of a relatively inexpensive and portable device for the widespread screening of lung cancer.