A team led by scientists from the Swedish universities of Linköping, Lund and Gothenburg injected a cocktail of chemicals into the brain, heart and tail fin of zebrafish and into the nervous system of medicinal leeches. Through an ingenious system that takes advantage of the tissue’s biological properties, these chemical substances formed a gel in the animals capable of conducting electricity, something useful for studying the functioning of the brain.
The results, published this week in Science, pave the way for making fully integrated electronic circuits in living organisms.
“For several decades, we have tried to create electronics that mimic biology. Now we let biology create the electronics for us”, comments work leader Magnus Berggren from the University of Linköping.
To bridge the gap between biology and technology, researchers have developed a method to create soft, substrate-free, electrically conductive materials in living tissue.
Linking electronics to biological tissue is important for understanding complex biological functions, fighting brain diseases and developing future human-machine interfaces.
However, conventional bioelectronics has a fixed, static design that is difficult, if not impossible, to match signals from biologically living systems, notes a statement from the University of Linköping.
To bridge this gap between biology and technology, the researchers developed a method to create soft, substrate-free, electrically conductive materials in living tissue.
Linköping University researchers Xenofon Strakosas, Magnus Berggren, Daniel Simon and Hanne Biesmans. /Thor Balkhed
Enzymes that act as assembly molecules
By injecting a gel containing enzymes that act as assembly molecules, the scientists were able to grow electrodes in tissue from zebrafish and medicinal leeches.
Specifically, in experiments conducted at Lund University, the team was able to form electrodes in the brain, heart and caudal fins of zebrafish and around the nervous tissue of leeches. The animals were not damaged by the injected gel or affected by the formation of the electrodes.
The structure of the injected gel changes when it comes into contact with substances in the body, making it a conductor of electricity.
According to the researchers, the structure of the gel changes when it is in contact with substances in the body, making it a conductor of electricity.
The body’s endogenous molecules are sufficient to trigger the formation of electrodes. There is no need for genetic modification or external cues, such as light or electrical energy, which were needed in previous experiments.
“New paradigm in bioelectronics”
This study, according to those responsible, paves the way for a “new paradigm in bioelectronics”. If before it was necessary to implant physical objects to initiate electronic processes in the body, in the future it will be enough to inject a viscous gel, they say.
The researchers also demonstrate that the method can direct electronic conductive material to specific biological substructures, thus creating suitable interfaces for nerve stimulation.
In the longer term, it may be possible to make electronic circuits fully integrated into living organisms, they say.
“Our results open up entirely new avenues for thinking about biology and electronics. We still have many problems to solve, but this study is a good starting point for future research”, emphasizes Hanne Biesmans, co-author of the work.
Reference:
M. Berggren et al. “In vivo metabolite-induced fabrication of substrate-free organic bioelectronics”. Science (February 2023)
