Cyborg cockroaches power tiny fuel cells

Posted by Emma Woollacott

Case Western Reserve University scientists say they've taken a big step towards the creation of insect cyborgs by discovering how an insect’s internal chemicals can be converted to electricity.

The electricity could power sensors or recording devices, or control the bug, which could be used for anything from disaster response to spying.

"It is virtually impossible to start from scratch and make something that works like an insect. Using an insect is likely to prove far easier,” says chemistry professor Daniel Scherson.

"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 key is exploiting two enzymes in the cockroach's digestive system to create an anode. The first breaks down trehalose, the sugar which itproduces from its food, into two simpler sugars called monosaccharides. The second enzyme oxidizes the monosaccharides, releasing electrons.

Current flows as electrons are drawn to the cathode, where oxygen from air takes up the electrons and is reduced to water.

The team inserted prototype electrodes into a blood sinus in the abdomen of a female cockroach, away from critical internal organs.And they found that power density hit nearly 100 microwatts per square centimeter at 0.2 volts, with a maximum current density of about 450 microamps per square centimeter.

The team's now working to improve the technique by miniaturizing the fuel cell so that the insect can run or fly normally and working on a low-power signal transmitter. They're also looking at adding a lightweight rechargeable battery.