Electric eels inspire new biomedical batteries

  Last updated January 24, 2018 at 5:00 pm


Electric eels are the inspiration for a new power pack design that could soon be used to drive biomedical devices.

Researchers have built the battery based on the cells that eels use to shock their prey. It consists of lumps of gels, arranged in rows much like the eel’s electrocytes.

The Electric eel (Electrophorus electricus). Credit: iStock

“Our artificial electric organ has a lot of characteristics that traditional batteries don’t have,” Thomas Schroeder, a chemical engineer at the University of Michigan in Ann Arbor, who co-led the research, was quoted by Nature as saying. “It isn’t as potentially toxic, and it runs on potentially renewable streams of electrolyte solution.”

Electric eels make electricity using thousands of specialised muscle cells called electrocytes. The process is deceptively simple – each electrocyte pumps positively charged potassium and sodium ions out of the cell, leaving more negatively charged ions inside.

Then, by suddenly releasing these electrons, each cell creates a voltage. While individual cells only produce a small charge, together they can deliver up to 600 volts, stunning virtually anything that comes near the animal.

Schroeder’s team mimicked the anatomy of electrocytes using 2,500 units of four different hydrogels made of polyacrylamide and water stacked together, generating some 110 volts. That is less powerful than an electric eel, whose cells are thinner and so offer less resistance.

The engineers envisage using the cells to power biomechanical devices by diverting the sugar naturally produced in the body to power cells, into an implanted electrical generator. “It’s conceivable that we might someday be able to use a scheme like our artificial electric organ to tap into different fluids in the body,” Schroeder was quoted as saying.

Credit: Schroeder et al. / Nature

The structure of the engineered cells can be seen in the illustration to the left.

The red gels in the bottom sheet of the illustration above contain saltwater, while blue ones contain freshwater.

Ions flow from red to blue through the green and yellow gels on the other sheet that bridge the the gaps.

The green gel lumps only allow positive ions to flow, while the yellow ones only allow negative ions.

So positive ions flow into the blue gels from one side, while negative ions flow in from the other, creating a voltage across the blue gel.

The research was published in the journal Nature.

About the Author

Bill Condie
Bill is former Head of Publishing at the Royal Institution of Australia. Previously he was Publisher of the popular science magazine, Cosmos, based in Melbourne, Australia. Bill has been a journalist for more than 30 years and his work has been published in Cosmos magazine, The Guardian, The Observer, The Times, The Daily Telegraph and the London Evening Standard.