Diamond coated electrodes are forever

By Ali Green

20 June 2017

Diamonds are helping us to advance bioelectronic medicine, brain-machine interfacing, sensors and basic neuroscience.

“Diamonds are forever” sang Shirley Bassey in the iconic 1971 Bond movie.

“They are all I need to please me, they can stimulate and tease me…”.

Well we’ve discovered another pretty cool way for diamonds to stimulate, and it’s not one you might easily guess!

Together with Deakin University, Melbourne University, the Melbourne Centre for Nanofabrication and the Fraunhofer Institute, we’re developing diamond coated carbon fibre electrodes.  These little gems are presenting an exciting opportunity for bioelectronic medicine, brain-machine interfacing, sensors and basic neuroscience.

In order for our body to control and regulate itself it relies on a complex network of neural circuitry. For people with debilitating conditions like epilepsy, auto-immune diseases, migraines, and Parkinson’s disease, this network can be a bit off kilter, requiring bioelectric medical intervention to help it function normally. Bioelectronic medicine uses electrical impulses to target specific neural pathways in order to alter the commands sent to either the brain or organs without the need for drugs and their often unwanted side-effects.

A magnified image of the carbon fibre electrode coated in a layer of diamonds.

A magnified image of the carbon fibre electrode coated in a layer of diamonds.

To work, bioelectronic medicine relies on tiny electrodes to interface, ideally, with single nerves.  These electrodes also need to be biocompatible with our soft insides.

The electrodes currently used in these techniques are fabricated from metals or silicon and protected from corrosion by polymer (plastic) coatings. But these coatings can cause toxic immune responses in patients which can limit their long term effectiveness. A way around this is to use smaller bio-inert electrodes (those that won’t react with the host) that are mechanically compliant and have brain tissue-like density. Shining brightly as a potential solution is the diamond coated carbon fibre electrode.

A micro electrode: the black carbon fibre core is coated in an insulating diamond sheath. The waves represent electrical impulses.

A micro electrode: The black carbon fibre core is coated in an insulating diamond sheath. The waves represent electrical impulses.

A diamond’s properties include extreme hardness, biocompatibility, chemical inertness, anti-fouling, and electrical insulation. Combined with the excellent strength-to-weight ratio, small diameter, flexibility and conductivity of carbon fibre, diamond coated carbon fibre electrodes positively sparkle as an exciting, novel and previously unexplored class of electrodes for neuroscience.

This work builds upon our patented method for coating carbon nanotube yarns with diamond which was developed using Fraunhofer’s diamond deposition facilities and expertise in Germany. The team of Victorian researchers now has the opportunity to explore the extension of this methodology to carbon fibres and biomedical/sensor applications through collaboration with the nearby Melbourne Centre for Nanofabrication, part of the Australian National Fabrication Facility (ANFF), and the use of their new suite of diamond deposition systems.

It is hoped the development of these improved biocompatible micro-electrodes will advance the area of bioelectronics medicine and neuroscience and help a growing number of sufferers with debilitating conditions live fuller, more functional lives and shine bright like a diamond.

If you’re interested in partnering with us to take this research to the next level, get in touch!

You can read more about our shimmering work in carbon fibre here.