A research team at the University of Pittsburgh in the US has developed a new electrode to facilitate less invasive neural stimulation for the treatment of neurological conditions such as Parkinson’s disease.
Existing implants for neural stimulation come with a transcutaneous cable that deteriorates over time and could lead to tissue scarring, the team said.
The new electrode is untethered, ultrasmall and can be activated by light, instead of a cable. This approach is expected to have comparatively lesser damage.
University of Pittsburgh Swanson School of Engineering bioengineering assistant professor Takashi Kozai said: “Typically with neural stimulation, in order to maintain the connection between mind and machine, there is a transcutaneous cable from the implanted electrode inside of the brain to a controller outside of the body.
“Movement of the brain or this tether leads to inflammation, scarring, and other negative side effects. We hope to reduce some of the damage by replacing this large cable with long wavelength light and an ultrasmall, untethered electrode.”
The team developed a carbon fibre implant of 7-8 microns in diameter and applied a photoelectric effect to stimulate it.
Photoelectric effect involves the use of a particle of light, or a photon, that causes a local change in the electrical potential of the target object.
The researchers used a phantom brain and a two-photon microscope to assess if the stimulation via electrical potential from the photoelectric effect is in a way similar to standard neural stimulation.
It was found that the photostimulation was effective. Activated cells were observed to be closer to the electrode, compared to electrical stimulation under similar settings, indicating better spatial precision.
Kozai added: “What we didn’t expect to see was that this photoelectric method of stimulation allows us to stimulate a different and more discrete population of neurons that could be achieved with electrical stimulation.
“This gives researchers another tool in their toolbox to explore neural circuits in the nervous system.”
The team is currently working on advancing the new technology, including reaching deeper tissue and wireless drug delivery.