3D-printed hydrogels mimic eel organs and can act as salt-based rechargeable batteries

While scientists have always derived inspiration from the animal kingdom, 3D printing is taking it to the next level. Through the use of a special hydrogel, researchers have just developed artificial eel organs that produce electricity. As a result, they have tapped into a potential battery that converts salt and water into power. This could allow a source of electricity that is compatible with bio-technology.

The research is a joint-project between University of Fribourg’s Adolphe Merkle Institute, the University of California San Diego, and the University of Michigan. The team decided to reverse-engineer the process by which eels produce electric shocks.

“The eel polarizes and depolarizes thousands of cells instantaneously to put out these high voltages,” said Max Shtein, a Michigan U associate professor and co-author of the study. “It’s a fascinating system to look at from an engineering perspective—its performance metrics, its fundamental building blocks and how to use them.”

Eels produce electricity by polarising the salts within their bodies in a process known as transmembrane transport. Eels can generate 600V and 100W of power by positively charging the sodium and potassium in their bodies. As the charge is set to positive, they rush to eels head, leaving negative charges in its tail end. This difference in polarity produces a powerful electric charge.

To mimic this effect, they had to produce hydrogels that could copy transmembrane transport. The hydrogels consist of a series of water-based polymer blends making up soft, flexible battery-like devices. Instead of potassium, the researchers are using another sodium-based compound, table salt (NaCl). The researchers dissolved the salt in water-based hydrogel and then printed it on a plastic sheet.

Applications

The hydrogel is remarkably similar to the electrocyte compartments found in an eel. 612 artificial eel cells can generate enough power to match that of a household outlet, i.e. 110 Volt. The importance of such an achievement cannot be understated.

This can have multiple applications. For one thing, it provides electricity but is also compatible with biology. This effectively allows it to be a godsend towards biotech researchers. Similarly, the applications inside of medical devices that have to be present in the human body are countless. Items such as pacemakers could have more efficient batteries.

Another application of the technology could be in that of bionic parts. Cyborg parts would be far easier to produce with this sort of hydrogel as a power source. While that is far in the future, it does lay the groundwork for a lot of interesting and radical ideas about the integration of technology and biological systems.