Spring 2008 Newsletter

Electrode Evolution

This bioengineering partnership led to two novel electrodes that require little skin preparation

Physicians have been using electroencephalography, or EEGs, for years to measure the electrical activity in the brains of their patients. But while the computer technology used to process the signals has advanced over the years, the electrodes themselves haven't changed much. That is, until Mingui Sun—professor of neurological surgery, bioengineering, and electrical engineering—and his collaborator, Tracy Cui (pronounced "tswee"), assistant professor of bioengineering, brought the traditional electrode into the 21st century.

Traditionally, Sun says, a technician would have to shave patches of a patient's scalp, prepare the skin, and then fasten each electrode to the head before the EEG testing could even begin.

"It requires multiple steps and can take as long as five minutes for one electrode," Sun says of the EEG preparation process.

The problem has been compounded, he says, particularly in the research field, where scientists are beginning to use high-density arrays for EEG tests, which means that hundreds of electrodes are placed on the scalp. So Sun designed a fingertip-sized metallic electrode that literally screws onto the skin and around any hair without requiring any preparation. The design includes tiny teeth on one end of the electrode that lightly but firmly grip the outer layer of skin when twisted onto it.

At the same time, Cui had been conducting research with conductive polymers when she teamed up with Sun on a research grant. The result: a new electrode made from a conducting polymer hydrogel. The water that is held within the gel allows ionic current flow across the skin, and the conducting polymer facilitates the conversion of the signal from ionic to electrical. And like Sun's other new electrode, this nonmetallic one likewise requires little manual preparation.

The hydrogel electrode has another added benefit. Cui says it has potential in the consumer gaming industry as an electrode that could provide a brain interface for a new generation of video games.

"Whether the electrode interface can be used for clinical or recreational purposes doesn't matter to me," she says. "But the science is almost done here."

Done, indeed, thanks to this research partnership with Sun.

"When I first started, I was trying to find collaborators," Cui says of her research partnership. "And we were in the same department."

They also both happened to be native Chinese, which helped them communicate more effectively. Moreover, their areas of expertise didn't overlap. "I have an electronics background, but I don't have any materials science experience," Sun says. "Tracy does. But we understand each other. It makes the collaboration very powerful."

Sun says their big challenge now is to be able to design workable prototypes that would allow for cheap manufacturing of the finished products. At this point, he says, "It might cost more, but it will cut labor costs."

Says Sun of the collaboration: "It has been a very good experience, no question about it."

Reprinted with permission from the University of Pittsburgh Office of Technology Management.

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