Electronic nose under test
The fusion of nature with nanotechnology promises to enhance the quality of life for every citizen in society. One area with huge potential is electronic sensor technology. The reduction or removal of human involvement in the detection of toxic substances could vastly improve safety and accuracy standards in a range of applications. The aptly named SPOT-NOSED project, funded by the EU, aimed to develop olfactory nano-biosensor arrays. Nanosomes some 40 to 60\;nm in size were produced that housed the olfactory receptors. These were then immobilised onto solid supports on a sensor chip. Following tests to verify the attachment of the nanosomes, the response of the olfactory receptors to odorant molecules was monitored. Odorant molecules can be very small and their binding to the receptors cannot therefore easily be detected. The researchers therefore applied Surface plasma resonance technology using a BIAcore instrument to detect the biochemical reactions involved in the olfactory response. Levels of Golf, a G protein that mediates biochemical cascades leading to the olfactory response, were measured. Despite the fact that immobilisation of nanosomes was not verified, Golf was detected in its active form when heptanal odorant stimulated its release. Remote sensing can mean the removal of danger during environmental monitoring. There is also potential for a vast improvement in the accuracy of testing in the health care and food safety areas. Due to the natural specificity of olfactory receptors, the electronic biosensor can be designed according to the target odorant.
