A sensor made up of gold nanoparticles can distinguish the breath of lung-cancer patients from healthy individuals in a high-humidity atmosphere, reports a study online in Nature Nanotechnology this week. This sensor may have the potential to form the basis of an inexpensive, non-invasive diagnostic tool for lung cancers.

Breath testing is known to link specific volatile organic compounds (VOCs) in exhaled breath to medical conditions. Various methods exist to measure these compounds but current techniques are expensive, slow and require the cancer bio-markers to be concentrated before measurements. Hossam Haick and colleagues report a portable sensing technology that can distinguish the breath of cancer patients from healthy volunteers rapidly, without needing to pre-treat or dehumidify the breath samples in any way.

The nine-sensor array consists of gold nanoparticles functionalized with different organic groups that respond to various VOCs that are relevant to lung cancer. The team simulated healthy and cancerous breath made from artificial mixtures of VOCs and tested them using this sensor. The two breath types were clearly distinguishable using pattern recognition, and the results correspond well with those gathered in experiments using real breath.

The device is expected to be relatively inexpensive, portable and amenable for widespread use in the clinic.