Electric nerve implants serve dual functions: they can either stimulate or block signals in specific nerves. For example, they may alleviate pain by inhibiting pain signals or restore movement in paralyzed limbs through electrical stimulation of nerves. Such implants are also used for standard nerve monitoring during surgeries, especially near the spinal cord where nerve fibers are dense. Despite providing direct access to nerve fibers, these implants pose inherent risks. Researchers have now developed tiny, flexible devices that can wrap around individual nerve fibers without causing them any damage.

At the University of Cambridge (Cambridge, UK), researchers have combined flexible electronics with soft robotics to create these novel devices, potentially transforming the diagnosis and treatment of disorders such as epilepsy and chronic pain, or enhancing the control of prosthetic limbs. Existing methods for interfacing with peripheral nerves—the 43 pairs of motor and sensory nerves linking the brain and spinal cord—are generally bulky and often carry a high risk of nerve injury. The new robotic nerve ‘cuffs’ developed by the Cambridge team are designed to delicately grasp or wrap around delicate nerve fibers without inflicting damage. These ultra-thin cuffs, built using conducting polymers typically utilized in soft robotics, consist of two distinct layers. When exposed to minimal electrical currents—a few hundred millivolts—these devices can expand or contract. Remarkably compact, these cuffs can be compressed into a needle for injection close to a targeted nerve. Once electrically activated, they change their shape to wrap around the nerve, enabling both monitoring and modulation of nerve activity.

The combination of soft electrical actuators with neurotechnology presents a promising avenue for minimally invasive approaches to both monitoring and treating diverse neurological conditions. Experiments on rats demonstrated that these nerve cuffs require only tiny voltages to change shape, creating a self-sealing loop around the nerves without the need for surgical stitches or adhesives. Going forward, the researchers aim to extend testing to larger animal models and expect to initiate human trials in the coming years.

“Using this approach, we can reach nerves that are difficult to reach through open surgery, such as the nerves that control, pain, vision or hearing, but without the need to implant anything inside the brain,” said Dr. Damiano Barone from Cambridge’s Department of Clinical Neurosciences. “The ability to place these cuffs so they wrap around the nerves makes this a much easier procedure for surgeons, and it’s less risky for patients.” 

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