bio-hybrid implant gets paralyzed limbs moving again

People with prosthetics or paralyzed limbs may soon be able to move their arms or legs independently again, thanks to a new neural implant developed by Cambridge scientists. It works great on mice.

The biohybrid device improves the connection between the brain and the prosthetic or paralyzed limbs. Using flexible electronics and a layer of human stem cells – the reprogrammable source cells, which in this case act like muscle cells – nerves from the shoulders or hips fit into an artificial arm or leg without scar tissue forming. at the site of attachment. And this is crucial.

Stem cells prevent scar tissue
Previous attempts to use neural implants to restore limb function have failed, among other things, because scars have formed around the electrodes within days. As a result, the neural signal deteriorates and eventually is completely lost. The team’s solution to preventing scar tissue is ingenious. By sticking a layer of muscle cells between the electrodes and living tissue, the lab rats maintained the signals throughout the experiment, for 28 days. This is unique in this relatively new branch of science.

Cell therapy meets bio-electronic
According to neuroscientists, the key to successful nerve regeneration lies in the combination of cell therapy and bioelectronics. They have created a unique device that overcomes the shortcomings of both disciplines. As a result, the functionality and sensitivity of the implant have been greatly improved. A number of follow-up studies are still needed before the device can be used in humans, but the team is confident they are on the right track.

Nerves lend a hand
It is still virtually impossible to repair a broken or severed nerve. The nerves cannot or hardly regenerate. So broken nerve pathways need a helping hand. “If someone loses their arm or their leg, the nervous system will continue to send signals. The big challenge in integrating artificial limbs and restoring arm or leg function is to transmit the information from the nerve to the limbs so that the function of the arms and legs is restored,” explains Damiano Barone, a researcher at Cambridge.

First time
It is the first time that stem cells are used in a living organism in this way. “These cells give us a lot of room to move and control. We can tell them how to behave and check in the meantime if everything is fine. Because we place stem cells between the electronics and the body, the body does not recognize the electrodes. It only notices muscle cells and therefore does not create any scar tissue,” says Barone. In this way, it was possible to send nerve impulses from the motor part of the rat’s brain to the prosthetic legs. Four weeks later, the neural bridge was still working perfectly.

Brain-machine interfaces
“This interface could revolutionize the way we interact with technology,” said researcher Amy Rochford. “By connecting living human cells to bioelectronic hardware, we have developed a system that can communicate with the brain in a more natural and intuitive way. This offers new possibilities for prostheses, but also for brain-machine interfaces and even the improvement of cognitive skills is on the agenda.

“It was very uncertain that our research would bear fruit,” said Professor George Malliaras. “It’s one of those projects where you don’t know if it will take two years or ten years to see results, but it went extremely well. We are very happy that it worked. »