Surgically implanted neurostimulators increasingly used to treat neurological disorders incorporate platinum due to the element’s excellent conductivity and biocompatibility. Platinum is also subject to irreversible electrochemical dissolution and degrades over time after implantation in the brain, releasing neurotoxic Application of a graphene coating reduced platinum dissolution in fractal electrodes by 97%. Source: Purdue Universitybyproducts and damaging surrounding tissue. Purdue University researchers demonstrated that adding a monolayer of graphene to platinum microelectrodes is effective as a protective solution.

Platinum dissolution rates were compared for circular and fractal shaped electrodes with or without monolayer graphene coating. The team also analyzed the electrochemical characteristics of these microelectrodes before and after a prolonged stimulation period to quantify the effects of platinum dissolution and graphene protection. The charge transfer performance of the fractal devices was superior, but the dissolution rate of bare fractal microelectrodes was faster than the dissolution of circular ones. Application of a graphene coating reduced platinum dissolution in fractal electrodes by 97%, and charge transfer capacities were maintained.

The research indicates great potential for graphene to improve neurostimulator device longevity and patient safety at a time when applications for neurostimulator implantation are expanding.