Glassy Carbon Shows Promise as Implantable Electrodes

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Researchers have created a unique fabrication method for electrodes, baking carbon at high temperatures and in the process changing the material’s makeup to enable new applications. The research was backed by the Center for Sensorimotor Neural Engineering (CSNE), an NSF-funded Engineering Research Center (ERC) with headquarters at the University of Washington.


The process has produced a glassy carbon that, for one, might be used in implantable electrodes that are less subject to corrosion and the scarring response from surrounding tissue. The material could extend the use of electrodes planted under the skull and on the surface of the brain, often used to monitor neural signals—including for epilepsy patients being considered for surgery to control seizures.


The buildup of scar tissue limits the use of existing electrodes, typically made from metals like platinum and gold, to about eight weeks. The scar tissue blocks signals that researchers monitor to understand brain function and malfunction. Researchers at San Diego State University (SDSU), a member of CSNE, have developed the glassy carbon material and mounted it on a flexible base. The team is also developing ways to wirelessly clean corrosion off the carbon devices, further extending their usefulness as implants.

The glassy carbon material shows promise as electrodes that can adapt to inevitable physiological changes in the body while not damaging the host tissue. The two characteristics are difficult to combine in conventional materials because the ability of a substance to undergo changes is often accompanied by the formation of side products that interact with surrounding tissue and eventually harm it.

Besides the treatment applications, the new electrodes can be used by CSNE researchers to help learn more about the brain signals active in everyday activities, such as raising an arm or shaking someone’s hand. SDSU researchers also are exploring the use of these devices in deep-brain stimulation, which is currently FDA-approved for Parkinson’s disease, essential tremor, dystonia, and Tourette’s syndrome.