Make Power, Slowly: Micro Power With Snails0

Rachel Nuwer | Mon Apr 16 2012

“The human body generates more bioelectricity than a 120 volt battery,” said the character Morpheus in The Matrix. “Combined with a form of fusion, the machines had found all the energy they would ever need,” he gravely explained of a dystopian future in which soulless robots tend fields of inert human batteries.

The Matrix, of course, is science fiction—at least for humans. But for one snail, life as a battery recently became a reality. Researchers at Clarkson University in Potsdam, New York, successfully implanted the first continuously operating biofuel cell in a live snail. Between bouts of rest and feeding, the cell utilized the snail’s glucose as fuel for producing electrical power over a several month period.

The “electrified snail,” as the researchers call it, brings science one step closer to realizing the goal being able to extract micropower for activating tiny sensors or wireless transmitting devices for environmental monitoring, said Evgeny Katz, Clarkson University’s chair of chemistry and the senior author of the paper published in the Journal of the American Chemical Society. “It also may be interesting for homeland security or military operations,” he added.

Klatz and his colleagues’ research pursues an answer to one sub direction of this line of research: micropower. The counterpart to micropower occurs on the comparably macro scale of human beings and biomedicine. In theory, researchers could develop biofuel cells that could be implanted in a human body to provide energy for devices like pacemakers.

Researchers struck upon the idea of implantable biofuel cells more than 20 years ago. Katz’s snail experiment—and a similar operation he took part in that strung clams together and managed to generate enough electricity to rotate a small electrical motor—are only the fourth and fifth successfully implanted biofuel cells in living creatures. “There’s a big difference between something being potentially possible and actually doing it,” he said.

To accomplish this undertaking, the researchers inserted high-tech electrodes made from compressed carbon nanotubes into two small holes they drilled in the snail’s shell. They coated each of the conductive nanotubes with a different type of enzyme, or the proteins that catalyze chemical reactions in animal’s bodies. One enzyme coating pulled electrons from the snail’s glucose, and another used those electrons to turn oxygen into water. The net effect was an electric current.

The power and current produced by the snail, about 0.5 V, was quite small— much smaller than a 1.5 V AAA battery. However, the electrical energy produced by the hapless gastropod can be accumulated in an electrical condenser, which could release the energy over a period of time to power an external device, like a small video camera or a wireless environmental monitoring tool.

Unlike in The Matrix, the snail took regular breaks for feeding and relaxing in its tank before producing a new portion of electrical energy. Though the snail was limited in its movements during its battery shifts, the researchers don’t think the little guy was bothered too much. In the future, they plan to connect the bioelectrodes to a microelectronic device fixed to the animal’s body, which would allow the snail to go about its snail life as usual, or, maybe eventually, spy on the enemy.

Top image: Neohelix albolabris (Whitelip Snail) Courtesy Jeffrey Nekola and Matt Kuchta/University of Wisconsin-La Crosse