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RESEARCHERS have found a way to convert an insect’s internal chemistry into electricity, paving the way for fitting them with sensors or even control devices.

The team, from the US’ Case Western Reserve University, think its work could help create insect cyborgs, able to search collapsed buildings or act as remote-controlled spies. Though idea may sound as though it was pulled from the pages of science-fiction, the scientists claim it is surprisingly practical.

“It is virtually impossible to start from scratch and make something that works like an insect,” says chemistry professor Daniel Scherson. “Using an insect is likely to prove far easier. For that, you need electrical energy to power sensors or to excite the neurons to make the insect do as you want, by generating enough power out of the insect itself.”

The electricity is produced using a biofuel cell, which breaks down a sugar called trehalose into monosaccharides. These are then oxidised, releasing electrons that are drawn to the cathode, generating electricity. It was initially tested on cockroaches, which produce a constant flow of trehalose from their food. Despite the cell being implanted directly into their abdomens, the insects appeared to suffer no long-term damage.

“Insects have an open circulatory system so the blood is not under much pressure,” explains Roy Ritzmann, a biology professor at Case Western Reserve. “So this is really pretty benign. In fact, it is not unusual for the insect to right itself and walk or run away afterwards.”

The researchers found that the cell generated about 100 mW/cm² at 0.2 v, and are working towards a version small enough that the insects can run and fly normally. They are also looking to develop a version with a small rechargeable battery, able to survive inside the body for an extended period.

“It’s possible the system could be used intermittently,” says Scherson. “An insect equipped with a sensor could measure the amount of noxious gas in a room, broadcast the finding, shut down and recharge for an hour, then take a new measurement and broadcast again.”

Journal of the American Chemical Society DOI:10.1021/ja210794c