McKelvey School of Engineering Neurotechnologies

Bomb-sniffing grasshoppers: the next frontier for public security?

A bomb-sniffing grasshopper with sensor ‘backpack’ (Photo: Barani Raman)

Bomb-sniffing cyborg grasshoppers have been created by scientists to detect explosives such as TNT.

Academics at Washington University in Missouri tapped into the insects’ minds to monitor whether they were smelling explosives, and if so, what kind they were detecting. Or as the researchers put it, the “bio-hacked” grasshoppers play a similar role to a “canary in a coal mine”.

How does the science work?

The scientists essentially “hijack” the insect’s sense of smell, by implanting electrodes into their brains that can pick up electrical signals triggered when olfactory receptor neurons in their antennae detect chemical odours in the air. 

The signals are then transmitted wirelessly to the scientists’ computer from a “backpack” attached to the grasshopper, says New Scientist.

This gives the researchers a baseline reading of which parts of the grasshopper’s brain are activated when the insect smells chemical explosives.

When the grasshoppers then smell a new substance, the scientists can compare the new signal reading with the baseline reading.

If the same part of the brain that lit up for smelling chemical explosives subsequently lights up again, the likelihood is that the grasshopper is smelling chemical explosives.

Indeed, the scientists found that the groups of neurones activated by different smells were distinct enough to identify specific sets activated by specific explosives.

A total of seven grasshoppers were tested, and as a unit correctly identified chemical explosives with 80% accuracy.

In a paper outlining their research, the scientists conclude: “Our study provides the first demonstration of how biological olfactory systems [sense of smell] can be hijacked to develop a cyborg chemical sensing approach.”

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