Korean researchers revive severed nerves with artificial neural conduit, restoring finger movement in primates

South Korean researchers have developed an artificial neural conduit capable of reconnecting severed nerves and restoring finger movement and sensation. A year-long experiment on rhesus macaques — whose hand structure and function closely resemble those of humans — confirmed that nerves regrew and hand function recovered.

A research team led by Jung Young-mi, a principal researcher at the Korea Institute of Science and Technology's Biomaterials Research Center, announced Wednesday that it had developed a multi-fascicular nerve guidance conduit (MFNGC) modeled on the actual structure of peripheral nerves. The work was carried out in collaboration with a team led by Professor Park Jong-ung of Korea University College of Medicine and the National Primate Research Center at the Korea Research Institute of Bioscience and Biotechnology.

Severe damage to peripheral nerves in the hand or arm can cause a person to lose the ability to move their fingers or feel sensation. When the gap is long, surgeons typically perform autologous nerve grafting — harvesting healthy nerve tissue from elsewhere in the patient's body — but this sacrifices normal nerve tissue and is limited by the amount available.

Conventional artificial nerve conduits have also largely taken the form of a single hollow tube, which limits their ability to guide regenerating nerves in the correct direction.

The research team drew on the fact that peripheral nerves are composed of multiple fascicles. By analyzing the nerve structure in the wrist of rhesus macaques, the team created three small internal channels inside a single larger conduit. The conduit was made from PLCL, a flexible polymer that gradually degrades inside the body.

Notably, the design relies solely on the conduit's structure to create a pathway for nerve growth, without the use of cells or additional growth factors.

The team implanted the conduit into a 15-millimeter gap in the median nerve of a rhesus macaque's wrist and monitored changes over 12 months.

The time it took the monkeys to pick up small pieces of food with their fingers shortened progressively, and motor impairment scores improved. Electrical stimulation tests measuring muscle response showed that signals began reappearing in most subjects after six months.

After 12 months, newly regenerated nerves inside the conduit had organized into multiple fascicles resembling those of natural nerves, and myelin sheaths surrounding the nerve fibers had reformed.

The molecular weight of PLCL, the conduit material, had decreased by about 94 percent compared with before implantation, and no significant chronic inflammatory response was observed. The findings confirmed the material's potential as a medical device component that serves as a temporary scaffold during nerve regeneration before gradually disappearing inside the body.

The technology could be used in reconstructive surgery for patients who have severed nerves in the wrist or arm due to industrial accidents or traffic injuries. Because the conduit can be manufactured in advance and stored until needed, it eliminates the additional surgery required to harvest nerve tissue from another part of the patient's body. This reduces operating time and avoids complications such as sensory loss or neuroma at the donor site.

The research team said the conduit's advantages extend to commercialization as a medical device, since it requires neither cell culture nor special cold-chain storage. After further verification of efficacy and safety, standardization of the manufacturing process, and regulatory approval research, the team expects it to serve as a nerve regeneration medical device that addresses the limitations of autologous nerve grafting.

"We confirmed the regenerative potential of an artificial nerve conduit modeled on the fascicular structure of actual nerves in a primate whose hand is structurally similar to a human hand," Jung said. "We will expand the scale of verification and work toward clinical application of a domestically developed nerve regeneration medical device."

The findings were published in the latest issue of the international journal Bioactive Materials.