Researchers at Linköping University (LiU) in Sweden have created an artificial organic neuron that closely mimics the properties of biological nerve cells. This artificial neuron can stimulate natural nerves, making it a promising technology for various medical procedures in the future.

At the LOE Organic Electronics Laboratory, work continues on the development of increasingly functional artificial nerve cells. In 2022, a team of scientists led by Associate Professor Simona Fabiano demonstrated how an artificial organic neuron could be integrated into a living carnivorous plant to control the opening and closing of its mouth. This synthetic neuron met 2 of the 20 characteristics that distinguish it from a biological neuron.

In their latest work published today (January 12) in the journal Nature Supplies , the same LiU researchers developed a new artificial nerve cell called a conductivity-based organic electrochemical neuron, or c-OECN, that closely mimics 15 of neurons. 20 neural features that characterize biological nerve cells and make them function like natural nerve cells.

“One of the major challenges in creating artificial neurons that effectively mimic real biological neurons is the ability to incorporate ion modulation. Conventional artificial neurons made of silicon can mimic many neural functions but cannot communicate via ions. In contrast, c-OECNs can uses ions to demonstrate several key properties of biological neurons,” said Simone Fabiano, Principal Investigator of the LOE Organic Nanoelectronics Group.

In 2018, a research group at Linköping University was one of the first to develop organic electrochemical transistors based on n-type conducting polymers, materials that can conduct negative charges. This made it possible to create complementary organic electrochemical circuits for printing. Since then, the group has been working to optimize these transistors so that they can be printed on a thin plastic foil with a printing press. As a result, it is now possible to print thousands of transistors on a flexible substrate and use them to develop artificial nerve cells.

In a newly developed artificial neuron, ions are used to control the flow of electronic current through an n-type conducting polymer, causing voltage spikes in the device. This process is similar to what happens in biological nerve cells. The unique material in the artificial neuron also allows the current to increase and decrease in a near-perfect bell-shaped curve similar to the activation and inactivation of sodium ion channels found in biology.

“A few other polymers exhibit this behavior, but only hard polymers are resistant to disordering, which ensures stable operation of the device,” says Simone Fabiano.

In experiments conducted in collaboration with the Karolinska Institute (KI), new c-OECN neurons were connected to the vagus nerve of mice. The results show that the artificial neuron was able to stimulate the nerves of the mice, causing a 4.5% change in heart rate.

The ability of an artificial neuron to stimulate the vagus nerve itself may pave the way for important applications in various forms of treatment in the long term. In general, organic semiconductors have the advantage of being biocompatible, soft and plastic, while the vagus nerve, for example, plays a key role in the immune system and the body’s metabolism.

The next step for researchers will be to reduce the energy consumption of artificial neurons, which is still much higher than that of human nerve cells. There is still a lot of work to be done to reproduce nature artificially.

“There’s still a lot we don’t fully understand about the human brain and nerve cells. In fact, we don’t know how the nerve cell uses many of these 15 proven functions. Imitating nerve cells can help us better understand the brain and create circuits that can perform mental tasks. Postdoctoral researcher “We have a long way to go, but this study is a good start,” says Padinhare Cholakkal Harikesh, lead author of the research paper.