How to Interface Graphene with Neurons

The wonder material--made of two-dimensional, nanoscale carbon--could be used to make electrodes for treating paralysis, according to British and Italian researchers.

Chris Newmarker

Italian and British researchers have shown that it is possible to interface graphene with neurons or nerve cells, maintaining the integrity of the cells.

The work could lead to graphene-based electrodes that could be implanted in the brain in order to restore sensory functions to amputee or paralysed patients, as well as people with motor disorders including Parkinson's disease or epilepsy, according to the research team, based at Cambridge University's Cambridge Graphene Centre and the University of Trieste in Italy.

Others had previously demonstrated that treated graphene can interact with neurons, but there was a very low signal to noise ratio from this interface was very low. The Cambridge and Trieste researchers figured out ways to work with untreated graphene, retaining the material's electrical conductivity and creating a much better electrode.

"For the first time we interfaced graphene to neurons directly," Laura Ballerini a neurosciences professor at the University of Trieste, said in a news release. "We then tested the ability of neurons to generate electrical signals known to represent brain activities, and found that the neurons retained their neuronal signalling properties unaltered. This is the first functional study of neuronal synaptic activity using uncoated graphene based materials."

The tiny graphene electrodes could help solve a major challenge for brain-machine interfaces. The modern electrodes used for such interfaces are based on tungsten or silicon, and suffer from partial or complete loss of signal over time as scar tissue forms around the electric insertion. Graphene is an attractive alternative because it is conductive, flexible, biocompatible, and stable inside the body.

The British and Italian researchers found their untreated graphene electrodes interfaced well with cultured rat brain cells. Using electron microscopy and immunofluorescence, the researchers found that the neurons stayed healthy, transmitted normal electric impulses, and showed none of the types of adverse reactions that lead to damaging scar tissue.

The next step is to investigate how different forms of graphene, from multiple layers to monolayers, affect the neurons, and whether tuning the material properties of graphene might result in new and unique ways to alter the synapses and neuronal excitability "Hopefully this will pave the way for better deep brain implants to both harness and control the brain, with higher sensitivity and fewer unwanted side effects," Ballerini said.

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Chris Newmarker is senior editor of Qmed and MPMN. Follow him on Twitter at @newmarker.

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