In order to link human brains to computers, the interface needs to be delicate enough not to damage nerve tissue, but resilient enough to last for decades.
The scientists published their findings in the journal Nature Materials. Scientists have come up with a stealthy neural interface made from a single carbon fiber and coated with chemicals to make it resistant to proteins in the brain.
This new microthread electrode is designed to pick up signals from a single neuron as it fires and is only 7 micrometers in diameter. This is the thinnest electrode that has ever been developed, and is about 100 times as thin as conventional metal electrodes used to study animal brains.
Researchers need long-lasting electrodes so that they can improve brain-machine interfaces. These systems, which are currently in preliminary studies, allow paralyzed people to control robotic limbs or a computer mouse. Using electrodes to record the firing of individual brain cells, scientists have learned to decode these signals as representing the movement of a rat’s whiskers or a quadriplegic’s effort to move his arms.
It could prove difficult to insert such a fine, flexible electrode into brain tissue and to secure them. But the researchers believed the small fibers are “a good thing, because they seem to be ‘ignored’ by the brain.” Conventional electrodes stop recording after a couple of years once scar tissue builds up around them. They researchers also coated its tip with a polymer that helps it pick up electrical signals.
Reference: “Ultrasmall implantable composite microelectrodes with bioactive surfaces for chronic neural interfaces” by Takashi D. Yoshida Kozai, Nicholas B. Langhals, Paras R. Patel, Xiaopei Deng, Huanan Zhang, Karen L. Smith, Joerg Lahann, Nicholas A. Kotov and Daryl R. Kipke, 11 November 2012, Nature Materials.