According to the researchers, from the Daegu Gyeongbuk Institute of Science & Technology, smaller conventional brain electrodes are generally easier on the brain tissue, but detect signals less well.
The new probe electrode starts with a thin gold base on which a forest of zinc oxide nanowires are grown to increase its effective surface area, thereby reducing connection impedance.
Subsequent coating with a thin layer of gold followed by a layer of the conductive polymer PEDOT (poly[3,4-ethylenedioxythiophene) strengthens the electrode and boost tissue compatibility without ruining flexibility.
A second part of the probe is the interconnect, between electrode and outside world, made from a mix of graphene and gold to combine graphene’s flexibility with gold’s conductivity.
“The researchers tested the probe and found it read rat brain signals very clearly, much better than a standard flat, gold electrode,” said the Institute. “The probe requires further clinical tests before widespread commercialisation.”
A wireless version is mooted.
For more information, ‘Enhancement of interface characteristics of neural probe based on graphene, ZnO nanowires, and conducting polymer PEDOT‘ is published in Applied materials and Interfaces.
Image provided by DGIST: artists impression of how the probes might be connected outside the brain – for probe detail photos see the paper abstract.