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Scientists build a better electrode with carbon nanotubes


This image, taken with a scanning electron microscope, shows a new brain electrode that tapers to a point as thick as a single carbon nanotube. Credit: Inho Yoon and Bruce Donald, Duke.

Since their inception, carbon nanotubes have often been touted as a ‘super material’ with potential applications ranging from space elevator cabling to next generation computer hardware. Often limitations in our ability to manufacture nanotubes make these ideas purely hypothetical, but neuroscientists at Duke University have figured out how to use their unique properties to make a better neural recording electrode.Recording signal from cells in the brain is a delicate process that currently uses electrodes made of glass or metal. Glass electrodes can be used to record from a single nerve cell, but are prone to breakage and so can’t be used in live animals. Metal electrodes can only record signal from a small population of cells, but are hardy enough to be used in vivo.

This is where the unique properties of nanotubes come in. Measured per unit of weight, nanotubes are around thirty times as strong as steel and much more flexible. They are also highly conductive, a combination that makes for an ideal brain electrode.

Duke researchers synthesized a millimeter long nanotube rod onto the end of a tungsten filament, then sharpened it using an ion beam at North Carolina State University. The finished product could record as well or better than a glass electrode, as well as cell populations the same as a metal electrode (when not fixed into one particular neuron). Even better, the new electrode is able to capture brain cell activity in living animals.

For now the technology needs refinement, and is very much still in infancy. The team of scientists behind the project have applied for a patent on the tiny spear-like electrode, and think it could be used for everything from basic science to brain-computer interfaces in the future.