A study coordinated by the International School for Advanced Studies in Trieste (SISSA) and the University of Trieste examines how effective graphene oxide flakes are at interfering with excitatory synapses, which could prove useful in new treatments for diseases like epilepsy.

Researchers at the University of Manchester and the University of Castilla -la Mancha have also taken part in this work, that may have discovered a new approach to modulating synapses using graphene oxide. The method uses graphene nano-ribbons (flakes) which buffer activity of synapses simply by being present. The researchers administered aqueous solutions of graphene flakes to cultured neurons in 'chronic' exposure conditions, repeating the operation every day for a week. Analyzing functional neuronal electrical activity, they then traced the effect on synapses.

In the experiments, size of the flakes varied (10 microns or 80 nanometers) as well as the type of graphene: in one condition graphene was used, in another, graphene oxide. It was discovered that the 'buffering' effect on synaptic activity only happened with smaller flakes of graphene oxide and not in other conditions. Also, the effect in the tested system was selective for the excitatory synapses, while absent in inhibitory ones.

According to the team, the origin of this selectivity is likely due to the mere presence of synapses, as it is known that in principle graphene does not interact chemically with synapses in a significant way. Currently there is no direct evidence, but the hypothesis is that there is a link with the sub-cellular organization of the synaptic space. In the excitatory synapses, the structure's organization allows higher exposure for the graphene flakes interaction, unlike inhibitory synapses, which are less physically accessible in this experimental model.

The scientists report that administering graphene flake solutions leaves the neurons alive and intact. For this reason the team thinks they could be used in biomedical applications for treating certain diseases. "We may imagine to target a drug by exploiting the apparent flakes' selectivity for synapses, thus targeting directly the basic functional unit of neurons" concludes the team.