Neurons on diamond

Diamond is bioinert, which means that living cells in contact with it do not evoke an immune response. Thus, diamond sensors or devices can be implanted into living animals, including humans, with no risk of inflammation or rejection, allowing the implant to remain in place for years, decades, or even the lifetime of the patient. Boron-doped diamond is electrically conducting, so it should be possible to pass electrical signals to and from neurons that are in contact with the diamond. This would form the basis of diamond electrodes used to simulate nerve cells in the brain or central nervous system, and possibly help to alleviate symptoms of Parkinsons', Motor Neurone Disease, epilepsy and other neurological disorders.

Another possibility is for signals to be received from the neurons into the diamond, which then pass these into an external computer which then acts on them accordingly. So, for example, an diamond electrode placed into the spinal cord of a paralysed patient might intercept the signals from the brain which normally would have gone to the legs, and then relay these to a computer which then operates a pair of robotic legs, allowing the patient to walk again. Similar diamond electrodes implanted into the brain may allow thought-controlled computers, machinery, aircraft, etc.

Neurons on diamond
Optical microscope picture of mice neurons
growing happily on a diamond substrate

Neurons on Patterned diamond
Optical microscope picture of mice neurons growing only on patterned diamond stripes,
and not on the Si areas separating them. The nuclei are stained blue whilst the dendrites are stained red.
Glial cells are green, and their absence shows that there is little
or no immune response from the cells.

At Bristol we have been working on this for ~4 years in collaboration with the Neuroscience Dept (Maeve Caldwell, Paul Nistor) here at the University. The first aim is to understand how cells (neurons and stem cells) behave when placed onto diamond surfaces. We have already shown that if the diamond is patterned into pathways, the neurons follow the diamond 'roads' and form a 2D living neural net. We are now beiginning to use electrically conducting doped diamond to study the fundamentals of how signals can be passed to and from neurons/diamond.