Adv. Healthcare Mater. http://doi.org/f2dkz9 (2013)

A human nose can selectively detect many different chemicals by means of a diverse set of olfactory receptors linked to sensory neurons. Mimicking this sensing capacity in devices termed bioelectronic noses could lead to the development of new sensing and diagnostic platforms. Now, Lim et al. have fabricated a bioelectronic nose consisting of single-walled carbon nanotube-based field-effect transistors (FETs) functionalized with olfactory nanovesicles that can selectively detect heptanal, a chemical biomarker present in the blood of lung-cancer patients. The specific human olfactory receptor that binds to heptanal was identified by a cell-signalling screening process. Then, mammalian cells expressing this olfactory receptor were used to produce nanovesicles containing the appropriate receptor on their surfaces. These nanovesicles were immobilized using charge–charge interactions on carbon nanotube channels within an FET device. The FET sensing system was shown to detect heptanal in samples of diluted human blood plasma spiked with the biomarker, at sufficiently sensitive concentrations that pre-treatment of the patients' blood would not be required in a clinical setting.