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Nanotech coating could lead to better brain implants

There are many barriers to creating stable, accurate, and long-lasting implants inside the brain. To quote from a local source:

One of the major problems with taking any external electrode array, and embedding it deep within the brain, is you have to cut your way down and embed the array in an open wound. There is currently no way around that.

So, whilst initially you gain a strong signal, and many if not most of the electrodes are hooked into the electrical output of nerves, over time micro scar tissue forms and cells begin to die back, away from the wound site. The electrical signals become fainter, as they have to fight through more and more dead matter, until finally, they are undetectable. When that occurs, the neuroprosthetic must be resited in the brain, a complex and dangerous operation.

Source: Fundamental Obstacles to Developing Reliable Neuroprosthetics

This article is concerned with an interesting way of bypassing much of that signal attenuation problem, allowing deep brain implants to stay functional en situ rather longer. Biomedical and materials engineers at the University of Michigan have developed a nanotech coating for such electrode arrays that actively inhibits the formation of scar tissue around the implantation.

With a far lesser build up of dead matter, signal strengths from surrounding neurons remain high for a much longer period of time.

The coating is made of a special electrically-conductive nanoscale polymer called PEDOT; a natural, gel-like buffer called alginate hydrogel; and biodegradable nanofibers loaded with a controlled-release anti-inflammatory drug.

PEDOT stands for Poly(3,4-ethylenedioxythiophene), which is quite a mouthful to speak, and is optically transparent, positively charged, and anti-static. In other words, it functions a little bit like a myelin sheath, and is detected by the brain's defenses as such.

The PEDOT in the coating enables the electrodes to operate with less electrical resistance than current models, which means they can communicate more clearly with individual neurons.

The alginate hydrogel, partially derived from algae, gives the electrodes mechanical properties more similar to actual brain tissue than the current technology. That means coated neural electrodes would cause less tissue damage.

The biodegradable, drug-loaded nanofibers fight the "encapsulation" that occurs when the immune system tells the body to envelop foreign materials.

The trick is to make the brain think the electrode array is one of these

At the moment, the first trials in non-human test subjects are underway. Clinical trials will be some time off. However, if this coating works even half as well as expected in the long term, there is the potential to have partially solved one of the greatest challenges of the brain-computer interface.


Fundamental Obstacles to Developing Reliable Neuroprosthetics

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Intrinsically Conducting Polymers

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