Researchers Move Closer to Low-Cost, Implantable Electronics

He suspects that such semiconductors could replace nerves in the body that have been damaged by disease or injury.

New technology under development at The Ohio State University is paving the way for low-cost electronic devices that work in direct contact with living tissue inside the body.

The first planned use of the technology is a sensor that will detect the very early stages of organ transplant rejection.

Paul Berger, professor of electrical and computer engineering and physics at Ohio State, explained that one barrier to the development of implantable sensors is that most existing electronics are based on silicon, andelectrolytes in the body interfere with the electrical signals in silicon circuits. Other, more exotic semiconductors might work in the body, but they are more expensive and harder to manufacture.

“Silicon is relatively cheap… it’s non-toxic,” Berger said. “The challenge is to bridge the gap between the affordable, silicon-based electronics we already know how to build, and the electrochemical systems of the human body.”

In a paper in the journal Electronics Letters, Berger and his colleagues describe a new, patent-pending coating that that they believe will bridge that gap.

In tests, silicon circuits that had been coated with the technology continued to function, even after 24 hours of immersion in a solution that mimicked typical body chemistry.

The project began when Berger talked to researchers in Ohio State’s Department of Biomedical Engineering, who wanted to build an insertable sensor to detect the presence of proteins that mark the first signs of organ rejection in the body. They were struggling to make a working protein sensor from gallium nitride.

“We already have sensors that would do a great job at detecting these proteins, but they’re made out of silicon. So I wondered if we could come up with a coating that would protect silicon and allow it to function while it directly touched blood, bodily fluids or living tissue,” Berger said.

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