Taken from MIT's Technology Review magazine:

Friday, May 19, 2006

This Is Your Brain on Nanotubes

Carbon nanotubes can send electrical signals to neurons and are being developed for retinal implants

By Katherine Bourzac

A branching neuron grown on a carpet of conductive single-wall carbon nanotubes. Researchers sent electrical signals to the neurons through the nanotubes, showing that the tubes might be a way to connect neurons to prosthetic devices. (Courtesy of Todd Pappas, University of Texas.)

Carbon nanotubes -- incredibly strong, electrically conductive, hollow molecules of carbon about a nanometer in diameter -- have for more than a decade been prized by materials scientists. They've added them to batteries to increase their surface area and are developing light-emitting nanotubes for telecommunications.

Now University of Texas researchers have demonstrated that mats of single-walled carbon nanotubes can communicate electrical signals to neurons, suggesting that the tubes could be used as an electrical interface between neural prosthetics -- devices used to replace damaged or missing nerves -- and the body. This is good news for those hoping to use nanotubes to stimulate or replace nerve cells in the eye, brain, and spinal cord.

The Texas researchers grew rat neurons on thick mats of carbon nanotubes seeded on flexible plastic sheets. Instead of treating the mats like a foreign surface, neurons take well to the nanotubes, says Todd Pappas, director of sensory and molecular neuroengineering at the University of Texas Medical Branch, who led the research. The nanotubes absorb an important neural protein and form a roughly textured carpet on which nerves grow readily. When Pappas and colleagues at Rice University sent an electrical charge across the sheet, the neurons responded with an electrical signal of their own, called an action potential, indicating that they got the message.

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