Soft and stretchable spinal cord implant mimics living nervous tissue
Swiss scientists have managed to create an elastic implant that moves with the spinal cord and restores the ability to walk in paralysed rats. Their elastic implant, called “e-Dura”, has been modeled on dura matter, the protective membrane of the brain and spinal cord.
So-called “surface implants” have reached a roadblock; they cannot be applied long term to the spinal cord or brain, beneath the nervous system’s protective envelope, otherwise known as the “dura mater,” because when nerve tissues move or stretch, they rub against these rigid devices. After a while, this repeated friction causes inflammation, scar tissue buildup, and rejection.
However, the e-Dura material, developed by EPFL scientists, contains stretchy electrodes that can move with the spinal cord and stimulate and record from neurons. When implanted in rats, the e-Dura caused less damage and inflammation than today’s rigid implants. Researchers say their biocompatible material could be the key to long-lasting neural therapies.
e-Dura has been designed specifically for implantation on the surface of the brain or spinal cord. The implant is placed beneath the dura mater, directly onto the 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. When implanted into rats, the e-Dura prototype caused neither damage nor rejection, even after two months. More rigid traditional implants would have caused significant nerve tissue damage during this period of time.
“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,” explains Professor Stéphanie Lacour, co-author of the paper, and holder of EPFL’s Bertarelli Chair in Neuroprosthetic Technology.
For the time being, the e-Dura implant has been primarily tested in cases of spinal cord injury in paralyzed rats. But the potential for applying these surface implants is huge – for example in epilepsy, Parkinson’s disease and pain management. The scientists are planning to move towards clinical trials in humans, and to develop their prototype in preparation for commercialization.