Researchers have developed a new type of neural implant that can restore limb function to amputees and those who have lost the use of an arm or leg.
In a study conducted in rats, researchers at the University of Cambridge used the device to improve connections between the brain and paralyzed limbs. The device combines flexible electronics with human stem cells (the body’s “reprogrammable” master cells) to better integrate with nerves and drive limb function.
Previous attempts to use neural implants to restore limb function have largely failed because scar tissue tends to form around the electrodes over time, interfering with the connection between the device and the nerve. was By sandwiching a layer of muscle cells reprogrammed from stem cells between the electrodes and living tissue, researchers found that the device integrated with the host’s body and prevented the formation of scar tissue. Cells survived on the electrodes for the duration of the 28-day experiment. This is the first time it has been monitored over such a long period of time.
By combining two advanced therapies for nerve regeneration—cell therapy and bioelectronics—into one device, the researchers hope to overcome the shortcomings of both approaches and improve functionality and sensitivity. says it can.
Although extensive research and testing will be required for human use, the device is a promising development for amputees and people with amputated limbs. The results are reported in Science Advances.
A major challenge in attempting to reverse injuries that result in limb loss or loss of limb function is the inability of neurons to regenerate and reconstruct the destroyed neural circuits.
“For example, if someone has an arm or a leg amputated, even though the physical limb is gone, all the signals in the nervous system remain,” says Dr. Damiano Barone of the University of Cambridge’s Department of Clinical Neuroscience Research. “The challenge in incorporating prostheses and restoring arm and leg function is extracting information from the nerves and delivering it to the limb to restore function.”
One way to address this problem is to implant a nerve in the large muscle of the shoulder and attach electrodes to it. The problem with this approach is that in addition to scar tissue forming around the electrodes, only surface-level information can be extracted from the electrodes.
For better resolution, implants for restoring function should extract more information from the electrodes. Also, to improve sensitivity, the researchers wanted to design something that works on the scale of a single nerve fiber, or axon.
“There’s a small voltage on the axon itself,” says Barone. “But when you connect with a muscle cell that has a much higher voltage, it’s easier to extract the signal from the muscle cell. That’s where you can increase the sensitivity of the implant.”
Researchers have designed a biocompatible, flexible electronic device that is thin enough to attach to nerve endings. A layer of stem cells reprogrammed into muscle cells was then placed over the electrodes. This is the first time that this type of stem cell, called induced pluripotent stem cell, has been used in vivo in this way.
“These cells give us tremendous control,” Barone said. “We can teach them how to behave and check them through experiments. By placing cells between the electronic device and the living body, the body does not recognize the electrodes, only the cells.” Therefore, no scar tissue is produced.”
A Cambridge biohybrid device was implanted in the forearm of a paralyzed rat. Stem cells that had been converted to muscle cells prior to transplantation were integrated with nerves in the forearm of rats. Although the rats’ forearm movements were not restored, the device was able to pick up signals from the brain that controlled movement. When connected to nerve rests or prostheses, the device may help restore movement.
The cell layer also improved the functionality of the device by increasing resolution and enabling long-term in vivo monitoring. Cells survived her 28-day experiment. For the first time, cells were shown to survive in long-term experiments of this kind.
The researchers say their approach has multiple advantages over other attempts to restore function in amputees. In addition to its ease of integration and long-term stability, the device is small enough that only keyhole surgery is required for implantation. While other neural interface techniques for functional recovery in amputees require complex patient-specific interpretation of cortical activity associated with muscle movement, the Cambridge-developed device uses ‘off-the-shelf’ cells. Therefore, it is a highly scalable solution.
In addition to potentially restoring function in people who have lost the use of their limbs, the researchers believe their device could also be used to control prosthetic limbs by interacting with specific axons responsible for motor control. said.
“This interface has the potential to revolutionize the way we interact with technology,” said co-lead author Amy Rochford of the School of Engineering. “By combining living human cells with bioelectronic materials, we create systems that can communicate with the brain in a more natural and intuitive way, providing new opportunities for prostheses, brain-machine interfaces, and even cognitive enhancement. It opened up possibilities.”
“This technology represents an exciting new approach to neural implants and we hope it will unlock new treatments for patients in need,” said co-first author Dr. Alejandro Karniser Lombarte. increase.
“It was a risky undertaking, but I am very happy that it worked,” said Professor George Marilas of the University of Cambridge’s School of Engineering, who co-led the study. “I don’t know if it took him two years or he took ten years for it to work, but he is one, but in the end it was done very efficiently.”
Researchers are currently working to further optimize the device and improve its scalability. The team filed a patent application with the support of Cambridge Enterprise, the university’s technology transfer arm. Cambridge Enterprise is also helping commercialize this technology.
Original: A ‘biohybrid’ device could restore function in paralyzed limbs
Than: Cambridge University
