Paralyzed Rats Walk Again With Biocompatible Flexible Neuroprosthetic Implant
A neuroprosthetic implant developed by EPFL scientists can be applied directly to the spinal cord without causing damage and inflammation. The soft cybernetic implant, which fuses electronics with biology, extracted cortical states in freely behaving animals for brain-machine interface and delivered electrochemical spinal neuromodulation that restored locomotion after paralyzing spinal cord injury.
The e-Dura implant is designed specifically for implantation on the surface of the brain or spinal cord. The small device closely imitates the mechanical properties of living tissue and can simultaneously deliver electric impulses and pharmacological substances. The risks of rejection and/or damage to the spinal cord have been drastically reduced.
In the future, such implants may help restore mobility in paralyzed patients or be used to treat neurological ailments, such as Parkinson’s disease and Tourette syndrome.
The research work is described in the article “Electronic dura mater for long-term multimodal neural interfaces,” published on January 8 on Science.
Prof. Stéphanie Lacour said:
Our e-Dura implant can remain for a long period of time on the spinal cord or the cortex, precisely because it has the same mechanical properties as the dura mater itself. This opens up new therapeutic possibilities for patients suffering from neurological trauma or disorders, particularly individuals who have become paralyzed following spinal cord injury.
The researchers tested the device prototype by applying their rehabilitation protocol – which combines electrical and chemical stimulation – to paralyzed rats. Not only did the implant prove its biocompatibility, but it also did its job perfectly, allowing the rats to regain the ability to walk on their own again after a few weeks of training.
While the implant is flexible and stretchable as living tissue, it includes electronic elements that stimulate the spinal cord at the point of injury. The silicon substrate is covered with cracked gold electric conducting tracks that can be pulled and stretched. The electrodes are made of an innovative composite of silicon and platinum microbeads. They can be deformed in any direction while still ensuring optimal electrical conductivity. Finally, a fluidic microchannel enables the delivery of pharmacological substances – neurotransmitters in this case – that will reanimate the nerve cells beneath the injured tissue.
The implant can also be used to monitor electrical impulses from the brain in real time. When they did this, the scientists were able to extract with precision the animal’s motor intention before it was translated into movement. That opens the possibility of interesting applications to Brain-Computer Interfacing (BCI), a field that is now picking up speed – and significant funding.
Images from EPFL and Wikimedia Commons.