A re-engineered electrode may advance the potential for brain-computer interface (BCI) technology to restore mobility and motor function to people who have suffered spinal cord injuries.

Electrodes made of glassy carbon. Electrodes used for such devices are typically fabricated with thin-film platinum, and can fracture and fall apart over time. Researchers from the Center for Sensorimotor Neural Engineering, a collaboration of San Diego State University with the University of Washington and MIT, tested glassy carbon as an electrode material.

This form of carbon is about 10 times smoother than granular thin-film platinum, so it corrodes less easily under electrical stimulation and lasts much longer than platinum or other metal electrodes.

A liquid polymer is patterned into the desired shape and heated to 1000 C (1832 F), at which point it becomes glassy and electrically conductive. After being cooked and cooled, the electrodes are incorporated into chips that read and transmit signals from the brain and to the nerves.

These enhanced BCIs are being used to record neural signals both along the brain’s cortical surface and from inside the brain at the same time. The researchers are studying whether precisely calibrated electrical stimulation can cause new neural growth within the spinal cord of animal models, with the goal of encouraging new neural cells to grow and replace damaged spinal cord tissue in humans.