4 Dec 2019

'Silicon neurons': Scientists develop artificial brain cells for bionic medicine

11:11 am on 4 December 2019

Researchers from Britain and New Zealand have built artificial neurons that could help people with conditions like Alzheimer's, certain types of heart failure, and other degenerative diseases.

A tiny chip on a person's finger.

The chip. Photo: Supplied/University of Bath

A team from the University of Bath used a combination of maths, computation and chip design to come up with a way to replicate in circuit form what nerve cells (neurons) do naturally.

Neurons carry signals to and from the brain and the rest of the body.

The tiny "brain chips" behave like the real thing and could one day be used to treat diseases such as Alzheimer's.

Scientists are interested in replicating them because of the potential that offers in treating diseases such as Alzheimer's where neurons degenerate or die.

Professor Alain Nogaret, from Bath's department of physics, said the novelty of their research was to transfer the electrical properties of brain cells on to synthetic circuits made from silicon.

"Until now, neurons have been like black boxes, but we have managed to open the black box and peer inside," he said. "Our work is paradigm-changing because it provides a robust method to reproduce the electrical properties of real neurons in minute detail."

Making artificial neurons that respond to electrical signals from the nervous system has been a long-time goal in medicine. Challenges included designing the circuits and finding the parameters that make the circuits behave like real neurones.

"We have managed to extract these parameters for biological neurons and plug these parameters into the synthetic circuits we have made," Prof Nogaret said.

The researchers replicated two types of neurones, including cells from the hippocampus, an area of the brain that plays a major role in memory, and brain cells involved in the control of breathing.

The work opens up a range of possibilities in repairing the neuron that have been lost to degenerative disease, including medical implants to treat conditions such as heart failure and Alzheimer's.

"Replicating the response of respiratory neurons in bioelectronics that can be miniaturised and implanted is very exciting," said co-researcher, Prof Julian Paton, a physiologist at the University of Auckland in New Zealand and the University of Bristol.

He said the neurons could act as the go-between between the brain and a synthetic limb.

"Such that through a thought process that you would have ... you could activate these silicon neurons to drive your prosthetic limbs."

"More than that, these devices could also then be connected to sensors in the prothetic limb such that you would sense - if connected to the right part of the brain of course - you would sense when you touched things and that would allow you to gauge the grip strength that you would need."

Another application would be to use the silicon neurons to control heart rate, saying it had some significant advantages over standard pacemakers.

"I think what we're on the verge here with this sort of approach is really advancing the bionics for medicine in the future, bionics meaning taking biologically inspired mechanisms and using engineering to mimic those processes.

He said he did not think it would be too long before silicon neurons were being used, considering there was already projects in the US and UK called "deep brain stimulation" to insert electrodes into the brain.

"Electrodes are put into the brain under very precise robotic control using imaging so we know exactly where they're going - we're avoiding blood vessels - and the safety records for those types of operations is phenomenally successful."

The research is published in the journal Nature Communications.