Researchers create artificial nerve cells that work almost like a biological nerve cell, according to a study published in the journal Nature Materials. A team from Linköping University (LiU), Sweden, says this can be used for various medical treatments in the future.
This work continues from a study published in 2020, where this team integrated a synthetic neuron into a carnivorous plant to control the opening and closing of its claw. However, these synthetic nerve cells only met 2 of the 20 characteristics of a biological nerve cell.
In this latest study, the researchers developed a new artificial nerve cell called “conductance-based organic electrochemical neuron” or c-OECN, which can mimic 15 out of the 20 neural features that characterise biological nerve cells. This makes it the closest to biological cells ever.
“One of the key challenges in creating artificial neurons that effectively mimic real biological neurons is the ability to incorporate ion modulation. Traditional artificial neurons made of silicon can emulate many neural features but cannot communicate through ions. In contrast, c-OECNs use ions to demonstrate several key features of real biological neurons”, says Simone Fabiano, principal investigator of the Organic Nanoelectronics group at LOE.
In the newly developed synthetic nerve cells, the team used ions to control the flow of electronic current in a conducting polymer, resulting in spikes in the device’s voltage. This is similar to what happens in biological nerve cells. The material used also allows the current to increase and decrease in an almost perfect bell-shaped curve identical to the activation and inactivation of sodium channels in nerve cells. “Several other polymers show this behaviour, but only rigid polymers are resilient to disorder, enabling stable device operation,” says Simone Fabiano.
In collaboration with researchers from the Karolinska Institute (KI), the new c-OECN neurons were connected to the vagus nerve of mice. The artificial neurons stimulated the mice’s nerves, causing a 4.5% change in their heart rate. The authors believe this could in the future pave the way for essential applications and medical treatments.
The next step is to reduce the energy needed to run these synthetic cells, which is still much higher than biological neurons. In addition, there is still much work for the artificial neuron to replicate nature artificially.
“There is much we still don’t fully understand about the human brain and nerve cells. In fact, we don’t know how the nerve cell makes use of many of these 15 demonstrated features. Mimicking the nerve cells can enable us to understand the brain better and build circuits capable of performing intelligent tasks. We’ve got a long road ahead, but this study is a good start,” says Padinhare Cholakkal Harikesh, postdoc and main author of the scientific paper.
Harikesh, P.C., Yang, CY., Wu, HY. et al. Ion-tunable antiambipolarity in mixed ion–electron conducting polymers enables biorealistic organic electrochemical neurons. Nat. Mater. (2023). https://doi.org/10.1038/s41563-022-01450-8