Researchers have used printed transistors to emulate the neurons and synapses of the biological system for artificial organic neuron.

In 2018, researchers at the Linköping University developed complementary and printable organic electrochemical circuits having both n-type and p-type polymers, which conducted negative and positive charges. This made it possible to build printed complementary organic electrochemical transistors. Since then, the group has subsequently optimised the organic transistors for manufacturing in printing presses on thin plastic foil. Thousands of transistors can be printed on a single plastic substrate. [1]

Figure 1. Artificial Nerve Cells Using Organic Semiconductors

Figure 1 shows for the first time, researchers demonstrate an artificial organic neuron, a nerve cell, that can be integrated with a living plant and an artificial organic synapse. Both the neuron and the synapse are made from printed organic electrochemical transistors.

On connecting to the carnivorous Venus flytrap, the electrical pulses from the artificial nerve cell can cause the plant's leaves to close, although no fly has entered the trap. Organic semiconductors can conduct both electrons and ions, thus helping mimic the ion-based mechanism of pulse (action potential) generation in plants. In this case, the small electric pulse of less than 0.6 V can induce action potentials in the plant, which in turn causes the leaves to close. [2]

From prostheses to soft robotics

The signal that drives the biological system to react is provided by the spiking frequency. During the study, the researchers also discovered that the neuron-synapse link exhibits a learning behavior known as Hebbian learning. It was seen that the synapse stores information, which increases the effectiveness of signaling.

"We’ve developed ion-based neurons, similar to our own, that can be connected to biological systems. Organic semiconductors have numerous advantages – they’re biocompatible, biodegradable, soft and formable. They only require low voltage to operate, which is completely harmless to both plants and vertebrates", explained Chi-Yuan Yang, post-doctoral researcher at the Laboratory of Organic Electronics. [3]

Learning behaviour

We’ve also shown that the connection between the neuron and the synapse has a learning behaviour, called Hebbian learning. Information is stored in the synapse, which makes the signalling more and more effective, says Simone Fabiano.The hope is that artificial nerve cells can be used for sensitive human prostheses, implantable systems for relieving neurological diseases, and soft intelligent robotics. [4]

References:

1. https://www.electronicsforu.com/news/whats-new/artificial-nerve-cells-organic-semiconductors
2. https://www.news-medical.net/news/20220223/Researchers-show-how-the-biological-system-can-be-steered-with-artificial-organic-neurons.aspx
3. https://interestingengineering.com/artificial-organic-neuron

Cite this article:

Thanusri swetha J (2022), Artificial Nerve Cells Using Organic Semiconductors, Anatechmaz, pp. 192