Two years ago a team of engineers from the University of Wisconsin-Madison engineers announced it had developed transparent sensors that could be used in brain imaging.
At the time, Zhenqiang (Jack) Ma and collaborator Justin Williams received a plethora of requests from research groups asking for more information on the devices.
The duo patented the technology through the Wisconsin Alumni Research Foundation, and saw the growing interest as an advancement in research.
"That little step has already resulted in an explosion of research in this field," said Williams, the Vilas Distinguished Achievement Professor in biomedical engineering and neurological surgery at UW-Madison, . "We didn't want to keep this technology in our lab. We wanted to share it and expand the boundaries of its applications."
That's what prompted the recent paper published this week in the journal Nature Protocols. Here the researchers describe 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, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison
Ma's group is a world leader in developing revolutionary flexible electronic devices. The see-through, implantable micro-electrode arrays were light years beyond anything ever created.
Now, the UW-Madison researchers are looking at ways to improve and build upon the technology, as well as to expand its applications from neuroscience into areas such as research of stroke, epilepsy, Parkinson's disease, cardiac conditions, and many others.
With the release of the work, they are encouraging other research groups to 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."
An excerpt from the paper:
"Transparent neural electrode arrays with ultraflexibility and biocompatibility have the potential to provide an optimal platform for various applications, including optogenetics and neural imaging. Neural electrode arrays with broad-wavelength transparency from the UV to the IR spectra are especially desirable, and they provide unique opportunities to advance techniques that would otherwise be impeded or impossible with conventional opaque metal electrodes. Transparent neural electrodes allow simultaneous observation of cells immediately beneath electrode sites during optical or electrical stimulation. Graphene, a novel 2D carbon-based material, is one of the most promising candidates for transparent neural electrodes, because the material has a UV to IR transparency of over 90%, in addition to its high electrical and thermal conductivity, flexibility, and biocompatibility. Here we present a protocol for the fabrication of the transparent graphene neural electrode array and its operation for electrophysiology, fluorescence microscopy, OCT, and optogenetics. The fabrication methods and the surgical protocols described herein are based on the graphene μECoG electrode array, which can be implanted on the surface of the cerebral cortex. However, this protocol may be amenable to fabrication and testing of a multitude of other electrode arrays used in biological research, such as penetrating neural electrode arrays to study deep brain, nerve cuffs that are used to interface with the peripheral nervous system (PNS), or devices that interface with the muscular system."