Protocols Introduced for Graphene-Based Array for Biophotonics Applications
MADISON, Wis., Oct. 17, 2016 — The fabrication and use of transparent graphene-based neural electrode arrays for applications in fluorescent microscopy, optical coherence tomography (OCT) and optogenetics have been described in detail by the researchers who developed the array. The arrays, which have broad-wavelength transparency from the UV to the IR spectra, could provide opportunities to advance techniques that may not be possible using conventional opaque metal electrode arrays.
When University of Wisconsin-Madison engineers announced in 2014 that they had developed transparent sensors for use in imaging the brain, requests for the device came flooding in.
"So many research groups started asking us for these devices that we couldn't keep up," said professor Zhenqiang (Jack) Ma."We described how to do these things so we can start working on the next generation."
A blue light shines through a clear, implantable medical sensor onto a brain model. See-through sensors, which have been developed by a team of UW-Madison engineers, should help neural researchers better view brain activity. Courtesy of Justin Williams research group.
The researchers’ fabrication methods and surgical protocols are based on
the graphene μECoG electrode array, which can be implanted on the
surface of the cerebral cortex.
Graphene has a UV to IR transparency of over 90 percent, in addition to its high electrical and thermal conductivity, flexibility and biocompatibility. Use of graphene allows through as much transmittance as possible, enabling the clearest image and allowing for the least light loss during optogenetic stimulation. Graphene has a flat transmittance spectrum, making it useful for both optogenetics experiments in the blue spectrum and multiphoton imaging in the IR.
The researchers’ wide-spectrum, transparent, graphene-based carbon-layered electrode array (CLEAR) technology has successfully demonstrated the ability to transmit optical stimulation through the array to the cortex of transgenic animals; to reliably record neural responses; and to interface with various in vivo imaging modalities.
"Our technology demonstrates one of the key in vivo applications of graphene. We expect more revolutionary research will follow in this interdisciplinary field," said Ma.
The protocols may help expand the reach of neurophysiological experimentation by enabling analytical methods that cannot be achieved using opaque metal-based electrode arrays. The researchers are looking at ways to improve and build upon the technology and seek to expand its applications from neuroscience into areas such as research of stroke, epilepsy, Parkinson's disease, cardiac conditions, and other areas of biological research. They hope other researchers do the same.
"This paper is a gateway for other groups to explore the huge potential from here," said Ma.
The research was published in Nature Protocols (doi: 10.1038/nprot.2016.127).
- A discipline that combines optics and genetics to enable the use of light to stimulate and control cells in living tissue, typically neurons, which have been genetically modified to respond to light. Only the cells that have been modified to include light-sensitive proteins will be under control of the light. The ability to selectively target cells gives researchers precise control.
Using light to control the excitation, inhibition and signaling pathways of specific cells or groups of cells...
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
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