Cyborg locusts get called up to sniff out bombs after scientists make breakthrough

A little while ago I wrote an article about a new type of drone – a living, controllable dragonfly drone, as well as new robo-bees and spy on the wall bugs, literally. But while it’s an interesting experiment, unless that is of course if you’re the dragonfly in question, what use are cyborg insects? Well, now we now – they can be used to sniff out bombs.

If you want to enhance a locust to be used as a bomb-sniffing bug though there are a few technical challenges that need solving before you can send it into the field. Is there some way to direct the locust - to tell it where to go to do its sniffing? And because the locusts can't speak yet, even though we’re creating animal universal translators, is there a way to read the brain of these cyborg bugs to know what they're smelling? And for that matter, can locusts even smell explosives?

Yes and yes to the first two questions. Previous research from Washington University in St. Louis has demonstrated both the ability to control the locusts and the ability to read their brains, so to speak, to discern what it is they are smelling. And now, thanks to new research from the McKelvey School of Engineering, the third question has been settled. The answer, again: 'yes.'

In a pre-proof published online in the journal Biosensors and Bioelectronics researchers showed how they were able to hijack a locust's olfactory system to both detect and discriminate between different explosive scents - all within a few hundred milliseconds of exposure.

They were also able to optimise a previously developed bio-robotic sensing system that could detect the locusts' firing neurons and convey that information in a way that told researchers about the smells the locusts were sensing.

"We didn't know if they'd be able to smell or pinpoint the explosives because they don't have any meaningful ecological significance," said Barani Raman, professor of biomedical engineering. "It was possible that they didn't care about any of the cues that were meaningful to us in this particular case."

Previous work in Raman's lab led to the discovery that the locust olfactory system could be decoded as an “or-of-ands” logical operation. This allowed researchers to determine what a locust was smelling in different contexts.

With this knowledge, the researchers were able to look for similar patterns when they exposed locusts to vapours from TNT, DNT, RDX, PETN and ammonium nitrate - a chemically diverse set of explosives.

"Most surprisingly," Raman said, "we could clearly see the neurons responded differently to TNT and DNT, as well as these other explosive chemical vapours."

With that crucial piece of data, Raman said, "We were ready to get to work. We were optimised."

Now they knew that the locusts could detect and discriminate between different explosives, but in order to seek out a bomb, a locust would have to know from which direction the odour emanated. Enter the "odour box and locust mobile."

"You know when you're close to the coffee shop, the coffee smell is stronger, and when you're farther away, you smell it less? That's what we were looking at," Raman said. The explosive vapours were injected via a hole in the box where the locust sat in a tiny vehicle. As the locust was driven around and sniffed different concentrations of vapours, researchers studied its odour-related brain activity. The signals in the bugs' brains reflected those differences in vapor concentration.

The next step was to optimise the system for transmitting the locusts' brain activity so the team focused the breadth of their expertise on the tiny locust. In order to do the least harm to the locusts, and to keep them stable in order to accurately record their neural activity, the team came up with a new surgical procedure to attach electrodes that didn't hinder the locusts' movement. With their new brain machine interface instrumentation in place, the neuronal activity of a locust exposed to an explosive smell was resolved into a discernible odour-specific pattern within 500 milliseconds.

"Now we can implant the electrodes, seal the locust and transport them to mobile environments," Raman said. One day, that environment might be one in which Homeland Security is searching for explosives.

The idea isn't as strange as it might first sound, Raman said.

"This is not that different from in the old days, when coal miners used canaries," he said. "People use pigs for finding truffles. It's a similar approach - using a biological organism - this is just a bit more sophisticated."

However, while it looks like locusts might be lining themselves up for a new career in the front lines of bomb detection they’re going to have to compete with new digital noses that are thousands times more sensitive than the best trained sniffer dog’s noses, and new mine hunting drones and neutrino sniffing Reaper drones that can detect bomb signatures from miles away … All of which is just yet another reminder than nothing ever stays still for long.