Swedish scientists have created electrodes by injecting a mixture of animal molecules into the brains of living animals. It was a successful test of growing a bioelectrode with organic gel. As a result, the line between biology and technology has become increasingly blurred.
Researchers at Linköping, Lund, and Gothenburg Universities in Sweden have successfully formed electrodes around the brain, heart and tail fins of live zebrafish and nervous tissue in medicinal leeches by triggering molecules in their bodies. Animals were not harmed by the injected gel and were otherwise unaffected by electrode formation.
This achievement, published in the February 24 issue of Science, is considered to have paved the way for the formation of integrated electronic circuits in living organisms that are completely different from existing physical chips. In other words, it paved the way for a new paradigm in biotechnology. Previously, implanted physical objects (such as semiconductors) were used for in-body bioelectronics, but in the future, injecting a viscous gel will suffice.
bioelectrodes were developed
As seen in the Brain Computer Interface (BCI) chip being studied by Elon Musk’s Neural Link Company, electronics use the way neurons work using electrical signals to interact with the brain and nerves to analyze their activity or treat injuries and disabilities. are trying to
However, while body tissues are mostly soft and flexible, bioelectronic electrodes are generally hard and rigid. Such discrepancies can cause bodily harm to the patient and damage the device.
In their latest study, Swedish researchers have developed a way to fabricate soft and flexible bioelectronics directly within biological tissue.
The research team says that the success of the bioelectrode growth technology secures the ability to turn living tissue into electronic materials, making it possible to manufacture microchips in living organisms in the long term.
Researchers have developed a way to fabricate soft, substrate-free, electronically conductive materials from living tissue to bridge this gap between biology and technology. They were able to grow electrodes in the tissue of zebrafish and medicinal leeches by injecting the enzyme-containing gel as ‘assembled molecules’. These gel electrodes lack the rigid supports found in conventional electronics, potentially making them more compatible with the human body.
The body’s internal molecules are sufficient to trigger electrode formation. It does not require genetic modification or external signals such as light or electric energy, which were required in previous experiments. Swedish researchers have succeeded in realizing this for the first time in the world.
When injected into biological tissue, the mixture of molecules developed by Swedish scientists chemically reacts with naturally occurring compounds such as glucose and lactase to form an electrically conductive gel.
“When it comes into contact with a substance on the body, the gel changes its structure and becomes electrically conductive, but not before it is injected,” said Xenophon Strakosas, a researcher at Lund University and one of the lead authors of the study. “Depending on the tissue, we can even tweak the composition of the gel to drive the electrical process.”
The researchers further showed that the method can target electron-conducting materials to specific biological substructures, thus creating interfaces suitable for nerve stimulation. Of course, not immediately, but in the long term, it may be possible to manufacture complete integrated circuits (ICs) in living organisms.
In experiments conducted at Lund University, the research team successfully formed gel electrodes with no signs of tissue damage around the zebrafish brain, heart, and caudal fin and nervous tissue of medicinal leeches. What’s more, they showed that the electrically conductive gel could connect the medical leech’s nerves with the electrodes of a small, flexible probe. Moreover, they were able to grow these electrodes from cow, pig and chicken muscle.
“By making smart changes to the chemistry, we could develop electrodes that are accepted by brain tissue and the immune system,” said Roger Olson, professor of medicine at Lund University. “The zebrafish is an excellent model for studying organic electrodes in the brain.”
One of the many challenges in this experiment was to consider the animals’ immune systems.
years of development
In 2015, it was Professor Roger Olsen who took the lead in research on growing electrodes in vivo after seeing the results of the development of the ‘electronic rose’ by researchers at Linkoping University.
One research problem was the important cellular structural differences between plants and animals. Plants have a hard cell wall that enables electrode formation, whereas animal cells are more of a soft mass. It took a lot of time to solve the problem of creating a gel with the right combination of structure and materials sufficient to form an electrode in this environment.
“Our findings open up entirely new ways of thinking about biology and electronics,” said Hanne Wiesmans, a PhD student at the University of Schöping and one of the lead authors. We still have a variety of issues to address, but this work is a good starting point for future research.”
“We’ve been trying to create electronics that mimic biology for decades,” said lead author of the study and material scientist Magnus Bergren, a professor at Linkoping University in Sweden. Now we let biology build the electronics for us.”
He said, “If electrons and electrodes are formed in a biological system, the invasiveness (the ability to invade tissues or cells) will be relatively much lower, even zero, compared to introducing hard and rigid standard electronics into soft biological tissue. ” he said.
In the near future, fabrication of these gel electrodes in living tissue could help improve electrical signal transmission between electronics and biology. “In the longer term, fundamentally new bioelectronic means such as novel nerve stimulation and recording protocols are possible,” Bergren said.
In the future, Swedish researchers say the new technique could make it possible to create fully integrated electronic circuits in living organisms.
Commenting on this achievement, Prof. Magnus Bergren said: “In the long run, fundamentally new bioelectronic tools such as novel nerve stimulation and recording protocols are possible. I am convinced that we can achieve something similar in mammalian models.” said.
Now, he says, these scientists are exploring molecular components and even chemicals that can guide molecular components to specific parts of the nervous system to create circuits.
Plenty of challenges before being used in humans
But there are many steps before this possibility becomes a reality. “We need to develop means to insulate wires and create device structures such as pn junctions or insulator-semiconductor junctions,” Bergren said, for example.
“Researchers, for example, need to make sure that these new bioelectronics have long-term stability in living animals,” says Professor Bergren. “Researchers should also show how to connect these soft electronics with other gadgets,” he added.
Currently, Elon Musk’s Neuralink is developing a brain transplant chip to allow humans to handle various electronic devices with only thoughts in their heads. The technology Neuralink is developing is a fully implantable, wireless, high-channel brain-computer interface (BCI) chip. It aims to enable people with paralysis to operate computers and mobile devices quickly and easily using their own neural activity directly.