A biocompatible implant based on graphene safely measures and predicts brain states.
Graphene Flagship scientists have developed a sensor based on CVD graphene that detects brain signals in a wide frequency band, from extremely low frequencies to high frequency oscillations. The sensor is biocompatible and could be used to measure and predict brain states. Furthermore, the graphene sensors could be used in chronic implants due to their high stability in the brain.
The study was conducted by scientists at Graphene Flagship partners the Catalan Institute of Nanoscience and Nanotechnology (ICN2), the Microelectronics Institute of Barcelona (CSIC), CIBER-BBN and ICREA, Spain, Ludwig-Maximilians University, Germany, and the University of Manchester, UK, in collaboration with Graphene Flagship partner Multi Channel Systems GmbH, Germany.
The consortium showed that graphene-based sensors grant access to an elusive low-frequency region of brain activity. Current methods to detect brain waves use metallic electrodes, which are ineffective at measuring very low-frequency activity – known as the ‘infra-slow’ region. Thanks to graphene’s sensitivity, scientists can now easily gather information from this region and paint a better picture of animals’ brain activity. This could form the basis for new types of neurotherapeutic medical technology.
Using a technology developed by ICN2 and the Microelectronics Institute of Barcelona, in the framework of the Graphene Flagship and the BrainCom European projects, Graphene Flagship scientists built an array of transistors that record and transmit activity information when implanted into the brain. The sensor has small channels on the surface: when they make contact with brain tissue, the electrical signals within the brain cause small changes in conductivity. These changes produce a signal and are recorded to create a brain activity ‘fingerprint.’
“With our array of devices, based on CVD graphene, we can record signals from the infra-slow region with very high accuracy,” Jose Garrido, from Graphene Flagship partner ICN2, Spain, explains. “In the brain, there is a correlation between lower and higher frequencies of brain activity, so the lower frequencies tend to dictate what the higher frequencies look like. We demonstrated that, by measuring the infra-slow activity, with frequencies below a tenth of a hertz, we can decode the ‘brain states’ of an animal.” Garrido believes this technology could lead to new treatments for brain disorders like epilepsy, as certain characteristic signal patterns could reveal ‘brain states’ likely to lead to seizures.