Body’s Sugar Transforms Cocktail Gel Into Electrodes Grown in Living Zebrafish; Experiment Could Improve Human-Machine Interfaces

Researchers used the body's natural sugar to turn an injected gel into a flexible electrode, and it worked.

Body Sugars Turn Injected Gel Into Electrode

A new study used the body's natural sugar to convert an injected gel cocktail into a flexible electrode without harming tissues after injecting it into a living zebrafish. The experiment showed no sign of ill effects on the fish where the electrodes grow.

These electrodes can be helpful in various applications, including studying how a biological system works to enhance human-machine interfaces. They can also be used in "bioelectronic medicine," such as brain stimulation therapies for depression, Parkinson's disease, and other health conditions, Science News reported.

Soft electronics aims to bridge the gap between biology and electronics hardware. Electronics tend to crack when the device is inserted, damaging the tissues in the process.

According to Magnus Berggren, a materials scientist at Linköping University in Sweden, all of the devices they produced, even if they were soft, still left a scar, which can degrade the performance of the electrode over time.

A previous study used electrical or chemical signals to power the transformation from chemical soup to conducting electrodes, but the zaps caused damage. Another study in 2020 solved the issue by genetically modifying cells in works to produce an engineered enzyme. However, the new method is even better because it achieved the same results without any genetic altercations.

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How Did The Experiment Go?

Berggren and his team opted to explore the natural energy source in the body - sugars. They used a gel cocktail containing oxidases that react with the sugar - glucose or lactate - to produce hydrogen peroxide, which activates another enzyme in the cocktail called hydrogen peroxidase, which is the catalyst needed to turn the gel into a conducting electrode.

Biomedical engineer Christopher Bettinger of Carnegie Mellon University in Pittsburgh said the strategy leveraged elegant chemistry and solved several technical challenges. Bettinger was not involved in the study.

To test if their technique works, the researchers injected the cocktail into the transparent zebrafish's brains, hearts, and tails. The gel turned blue when it became conductive, giving them a visual cue that it worked.

Materials scientist Xenofon Strakosas, also of Linköping University, was thrilled with the results, saying it was "beautiful" because they could see how the zebrafish's tail changed color, and they were aware that blue indicates polymer. Strakosas said when he saw the color change, he exclaimed, "It's really working!"

The fish in the experiment showed no signs of illness or tissue damage. The team showed that delivering current via soft electrodes could induce muscle constructions, and they could be paired with various wireless technologies in development.

Despite the success, Bettinger said they still need to determine the long-term performance of the implant. They have to ensure the electrode's stability and see if the body would react with the electrode materials, degrade it or produce toxic substances.

The results of the study were published in Science on Feb. 24.