Carbon materials are an extremely hot topic in science right now. Just today we previously covered a story involving a carbon nano-material. That story was about graphene, but there's also news about the closely related material of carbon nanotubes. In a press release on Eureka Alert, some scientists from Rice University discuss their attempts to use carbon nanotubes as electrodes in the brain.
Electrodes in the brain may sound like a very scary prospect, but it's actually extremely important for some people. Deep brain stimulation using electrodes is greatly improving the quality of life for people with Parkinson's. Electrical signals are sent to a specific part of the brain to counteract the tremors that the condition causes. Similar procedures are being investigated to treat a wide range of neurological conditions, including dementia and depression.
Despite the potential, it's still inserting a hard metal object into the soft mushy brain. But that is where carbon fibers seem to have the advantage. The team of chemical engineers from Rice initially developed spun fibers of carbon nanotubes for aerospace applications. They were successful in creating a material with high strength, flexibility, and conductivity. But they realized that these are also properties desirable in a brain electrode.
Millions of the nanotubes are in these fibers that are still only one quarter the width of a human hair, and extremely soft and flexible like a threat of silk. A 3 micron layer of biocompatible insulating polymer is also added, so that only the very tip of the fiber is conductive. Not only is the quality of electrical signal higher than conventional electrodes, but it also works two ways. The highly conductive carbon fibers can both receive and transmit electrical signals.
Unlike current brain stimulation implants, new ones using carbon could actively monitor brain activity and adapt the electrical output. In an initial tests of a mouse model of Parkinson's, the carbon electrodes were just as effective as metal ones while reducing inflammation and scar tissue. The softer and thinner fibers will make such implants generally more tolerated by the human body.
An issue to overcome still is precisely placing the electrodes, but improvements in that will rely more on brain imaging technology. Still, the scientists are excited by the potential improvements that carbon fibers could bring to neurobiology. In addition to the deep brain stimulation implants, it could generally improve various efforts to produce brain-machine interfaces, among other applications.
