The Smell Of Death

Scientists in Korea have developed a bioelectronicnose’ that can specifically detect a key compound produced in decaying substances. When food begins to rot, the smell that we find repulsive comes from a compound known as cadaverine. That is also the substance responsible for the stench of rotting bodies, or cadavers—hence the name. The compound is the result of a bacterial reaction involving lysine, which is an amino acid commonly found in various food products. A previous study has shown that a receptor in zebrafish has an affinity for cadaverine. To make this receptor in the laboratory, scientists have turned to Escherichia coli bacteria as a host cell because it can easily produce large quantities of proteins. However, the production of this receptor in E. coli has been a challenge because it needs to be embedded in a membrane.

In this study, a team of researchers led by Associate Professor Hong Seunghun at Seoul National University packaged the cadaverine receptor from the zebrafish into nanodiscs, which are water friendly, membrane-like structures. The researchers then placed the receptor-containing nanodiscs in a special orientation on a carbon nanotube transistor, completing the bioelectronic nose. During testing with purified test compounds and real-world salmon and beef samples, the nose was selective and sensitive for cadaverine, even at low levels. The researchers suggest that the detector could someday prove useful in natural disaster scenarios, to recover corpses for identification.

The findings have been published in the journal ACS Nano.