Researchers from the Daegu Gyeongbuk Institute of Science & Technology in Korea have used graphene to develop neural probes that are small, flexible and read brain signals clearly.
The probe consists of an electrode, which records the brain signal. The signal travels down an interconnection line to a connector, which transfers the signal to machines measuring and analyzing the signals. The electrode starts with a thin gold base. Attached to the base are tiny zinc oxide nanowires, which are coated in a thin layer of gold, and then a layer of conducting polymer called PEDOT. These combined materials increase the probe's effective surface area, conducting properties, and strength of the electrode, while still maintaining flexibility and compatibility with soft tissue.
Packing several long, thin nanowires together onto one probe enables the scientists to make a smaller electrode that retains the same effective surface area of a larger, flat electrode. This means the electrode can shrink, but not reduce signal detection. The interconnection line is made of a mix of graphene and gold. The researchers tested the probe and found it read rat brain signals very clearly, much better than a standard flat, gold electrode.
"Our graphene and nanowires-based flexible electrode array can be useful for monitoring and recording the functions of the nervous system, or to deliver electrical signals to the brain," the researchers explain.
The probe requires further clinical tests before widespread commercialization is enabled. The researchers are also interested in developing a wireless version to make it more convenient for a variety of applications.
In March 2017, researchers from the Graphene Flagship developed a new graphene-based device able to record brain activity in high resolution while maintaining excellent signal to noise ratio (SNR).