Insect noses to sniff out bad smells

Researchers at New Zealand's HortResearch Crown Research Institute are using insect smell receptors to develop biosensors that act as an artificial nose, capable of detecting volatile compounds.

"Insect receptors are good as they can be screened easily in a behavioural assay," said Richard Newcomb, head of the HortResearch team working on the project.

"And insects have a great sense of smell."

The researchers have isolated and expressed insect smell receptor genes in cell lines, where they are linked to signalling systems that cause the cell to fluoresce when the compound is detected by the receptor.

"We've never been able to detect compounds in real time before," Newcomb said.

The next step will be to incorporate the receptors into an artificial biolayer that can be linked to an electronic reporting system. The ultimate goal is a handheld sensor that can be used to instantaneously detect odours.

"Ultimately we could go to the airport and sniff for drugs or fruit across bags, or build a sensor into a production line to detect spoilt food on the go. There's machinery around that can do this kind of stuff, but not instantly and it is not miniaturised for convenience," said Newcomb.

According to Newcomb, the technology has potentially broad applications, from food processing uses and food quality analysis to biosecurity and defence applications. And it's not that far away -- he believes that proof of concept is two years away, and a working prototype device will be available within five years. Then it will be a matter of choosing the right applications to take forward.

"[The project has] been moving pretty fast so far," Newcomb said. "We though getting the receptors to work in cells would be slower, but it's gone quite smoothly."

And with a vast array of organisms possessing smell receptors suited to their particular environments, there are large numbers of receptor types that can be mined. For example, while Drosophila -- a fruit fly -- is tuned to the types of smells found in orchards, blowfly receptors may be useful for detecting the odours associated with rotting meat. Mice and dogs have far more active smell receptors than the relatively limited range used by humans. The potential also exists to use taste receptors to detect less volatile compounds.

The NZ team is working with two Australian scientists to develop the biosensor, including Monash Drosophila researcher Coral Warr and CSIRO Entomology's Stephen Trowell.