Artificial neurons connect with biological ones to control living plants

Nature is an endless source of inspiration for scientists, but our artificial devices usually interact poorly with real things. Now researchers at the University of Linkoping have created artificial organic neurons and synapses that can integrate with natural biological systems, and have demonstrated this by making Venus flytrap close on demand.

The new artificial neurons are based on earlier versions of the team, which were organic electrochemical circuits printed on thin plastic film. Because they are made of polymers that can conduct both positive and negative ions, these circuits form the basis of transistors. In a new study, the team optimized these transistors and used them to create artificial neurons and synapses and connect them to biological systems.

When transistors detect the concentration of ions with certain charges, they switch, producing a signal that can then be picked up by other neurons. Importantly, biological neurons work on the same ion signals, which means that artificial and natural nerve cells can be connected.

“We have developed ion-based neurons similar to ours that can be connected to biological systems,” said Chi-Yuan Yang, the study’s author. “Organic semiconductors have many advantages – they are biocompatible, biodegradable, soft and can be formed. Their work requires only low voltage, which is absolutely harmless to both plants and vertebrates.

To demonstrate the new system, the researchers connected their artificial neurons to a living Venus flytrap. And of course, the electrical impulses from the artificial neurons were strong enough to cause a flytrap to close their jaws, but at voltages below 0.6 volts, soft enough not to harm the plant.

Interestingly, the team says that neurons exhibit a form of memory known as Hebbian Learning, where reactivating certain synapses strengthens neurons on both sides, making this signal more efficient over time.

The team says the Venus flytrap was chosen for demonstration because of how clear the response is, but ultimately artificial neurons can be integrated with animal and even human neurons. They can bridge the gap between artificial and natural neurons for more sensitive prostheses, implants and robotics.

Other recent studies have succeeded in creating artificial synapses that connect to synthetic electronic systems using neurotransmitter chemicals as dopamine.

A new study was published in the journal The nature of communication.

Source: Linköping University