​Graphene Oxide Nanosheets Reshape Synaptic Function in Cultured Brain Networks

A recent paper published by Flagship researchers is a classic example of this approach (1). In this paper researchers studied how graphene and graphene oxide interact with neurons; the cornerstone cells of the brain. They found that, although neither forms of graphene affect the viability of the neuron cells, graphene oxide may be used to down regulate the neural signalling. This work, published in ACS Nano, is an example of how working with the 'safety by design' principle can lead to thinking about research results in a different way.

Understanding how the body might react to graphene is enormously important if the true potential of graphene in therapeutics is to be realised. For example, graphene has previously been shown to have the potential to help produce better deep brain implants – an important and unique therapeutic route (2).

The research in this most recent paper, led by Prof. Laura Ballerini from the International School for Advanced Studies (SISSA), Trieste, in Italy, looked at different types of graphene, pristine (unaltered) graphene and graphene that had undergone an oxidation to form graphene oxide. The graphene oxide used in this study had many different types of oxygen containing groups attached to it surface. This seemingly simple difference fundamentally altered the way that the graphene interacted with the neuron cells.  
 

The cells that had graphene oxide introduced were seen, unexpectedly, to have a significant down regulating of the neural signalling. This is thought to be because the flakes, well dispersed in biological solution, can interact with synapses, the sophisticated inter-neuronal signalling system that guarantees neuronal ability to process and transfer information. 

It was also discovered in this research that the size of the graphene oxide flakes made a big difference in its interaction with neural communication pathways. Small graphene oxide flakes showed more intricate and sophisticated signal tuning than bigger flakes.

The understanding that different types of graphene have different neural interactions gives us the opportunity to engineer safety into how we use graphene - 'safety by design'. By tuning graphene materials to reduce and prevent unwanted side effects then the safety of those potentially exposed to graphene flakes can be insured.

In some neurological disorders, where the symptoms are eased by the 'switching off' of certain neural segments in the brain, the targeted retardation of a set of neurons is a desired effect.

Prof. Maurizio Prato from the University of Trieste in Italy is the Graphene Flagship's member responsible for the health and environmental impact of graphene and here he talks further about this paper: “Our brain is usually not directly exposed to ambient agents. Also, there is not yet experimental evidence that graphene derivatives can trespass the blood-brain-barrier. Thus we believe our observations open more opportunities.”

In continuing support of the work on the safe use of graphene the Graphene Flagship is expanding its programme in this area into two separate work packages, one focused on Health and the Environment and the other on Biological Technologies. Prof. Ferrari, Director of the Cambridge Graphene Centre, and Science and Technology Officer of the Graphene Flagship, talked further about this important move, "the Flagship is supporting biomedical research and development based on graphene technology with an additional work package and a significant cash investment. Results emerging from flagship researchers show we are just scratching the surface when it comes to the potential of graphene and related materials in bio-applications".