Graphene Medical applications

Neurosurgeons get ready to bring graphene to the operating table

• By John Hewitt on May 1

Share This ArticleWhen any exotic new material is found researchers often ask the same questions. Can it store bits? Can it store energy? Sooner or later, particularly if the material is really exotic, someone wants to put it in your head. In a feature story for the latest issue of the journal Neurosurgery, doctors are looking to graphene to solve some of the most challenging issues in their field.

With graphene you can pretty much name your favorite physics phenomenon, and there will be some way that the material can be used to exploit it. Graphene is so thin that it’s transparent — but also, per gram, one of the most light-sensitive materials in the world. Unlike many other metamaterials, it is also a good absorber in the IR and UV ranges. What excites some neurosurgeons is that past a certain threshold of illumination, graphenedisplays what is called “saturable absorption” — beyond this illumination point ,graphene releases extra energy in the form of heat which can potentially be harnessed to kill tumors.

Graphene oxide fiber, up close and personal

Graphene’s high surface area (approximately 2630 square meters per gram) leads to remarkable conductivity. It also provides great access for various modifier molecules to bind or bioconjugate with it, and transform its behavior. Agents like poly(ethylene oxide), poly(vinyl alcohol), polyurethane, and poly(methyl methacrylate), can be used to generate all manner of useful graphene-polymer composites. Nowadays we don’t just have graphene, but also have its various derivatives like graphene fluoride, graphene oxide, and reduced graphene oxide (rGO). Not only does each form have unique material properties, but potentially unique ways of interacting with the tissues of the body.

One area that has been generating a lot of buzz in the neurosurgery field is the development of materials to bridge and even stimulate nerves. The authors suggest graphene may be ideal as an electroactive scaffold when configured as a three-dimensional porous structure. That might be a preferable solution when compared with other currently vogue ideas like using liquid metal alloys as bridges. Graphene has already been shown to make an ideal E-field stimulator and was even used in that capacity to enhance blood flow within the brain.

A view of the human hippocampus, with fluorescent proteins and confocal microscopy

Among the other things researchers can do with graphene is exploit the special property of having delocalized pi electrons on its surface. This allows energy to be readily exchanged with nearby neighbors. In practice, this becomes useful as a quencher of fluorescence. To do fast, real time fluorescence studies, the limitation is not so much how fast you can activate but rather how fast you can turn things down. Neurosurgeons have been turned on to the idea of intraoperative imaging during various oncologic and vascular procedures. Being able to rapidly turn on different tissues — and therefore see them — is a game changer in the surgical theater.

The authors go a little overboard though, in leaping to the idea that graphene could be useful in quantum computing applications — inside your head no less. We certainly applaud their vision, but might also suggest that getting quantum computers to “work” anywherewould be a more realistic goal for now. If all this talk of graphene has whetted your appetite, be sure to check out our feature on the wonderful world of wonder materials.