Engineers Reveal Fabrication Process for Transparent Sensors

MADISON, Wis.–In 2014, when University of Wisconsin-Madison engineers announced, in the journal Nature Communications, that they had developed transparent sensors for use in imaging the brain, researchers around the world took notice.

Then the requests came flooding in. "So many research groups started asking us for these devices that we couldn't keep up," said Zhenqiang (Jack) Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, in a release from the university.

Ma's group is at the leading edge of developing what it calls "revolutionary flexible electronic devices." The see-through, implantable micro-electrode arrays were said to be "light years beyond anything ever created."

Although Ma and collaborator Justin Williams, the Vilas Distinguished Achievement Professor in biomedical engineering and neurological surgery at UW-Madison, patented the technology through the Wisconsin Alumni Research Foundation, they saw its potential for advancements in research. "That little step has already resulted in an explosion of research in this field," said Williams in the release. "We didn't want to keep this technology in our lab. We wanted to share it and expand the boundaries of its applications."

In a paper published on Oct. 13, 2016 in the journal Nature Protocols, the researchers described in great detail how to fabricate and use transparent graphene neural electrode arrays in applications in electrophysiology, fluorescent microscopy, optical coherence tomography, and optogenetics. "We described how to do these things so we can start working on the next generation," said Ma.

Now, not only are the UW-Madison researchers looking at ways to improve and build upon the technology, they also are seeking to expand its applications from neuroscience into areas such as research of stroke, epilepsy, Parkinson’s disease, cardiac conditions, and many others. And they hope other researchers do the same.

"This paper is a gateway for other groups to explore the huge potential from here," said Ma. "Our technology demonstrates one of the key in vivo applications of graphene. We expect more revolutionary research will follow in this interdisciplinary field."

Funding for the initial research came from the Reliable Neural-Interface Technology program at the U.S. Defense Advanced Research Projects Agency.