Repairing damaged nerves with 3D printing

Nerves illustration

We've developed a 3D-printed biodegradable device to help the body repair itself.

Our scientists have used it to assist nerve damage repair in animal models.

Based on precise measurements of the animal model’s nerves taken from detailed 3D imaging, scientists printed a bespoke device to bridge the gap where nerves are severed.

The device is called a Nerve Guidance Conduit (NGC) and is made from biocompatible materials. NGCs help direct damaged nerve ends towards each other, so they can repair naturally.

It can take a long time for nerves to repair themselves though typical regeneration takes place between several months to a year. NCGs have a similar lifespan in that they will have degenerated by the time the nerves have regenerated themselves.

The team, which spans the Faculty of Engineering and the Faculty of Medicine, Dentistry and Health, believes that the process could be used to treat traumatic injuries.

In some cases, nerve damage can be so severe in trauma patients that they feel severe pain or complete loss of sensation. Nerve damage can also produce pain as a result of built-up scar tissue beneath the surface of the skin, which can also be unpleasant for the patient.

By aiding nerve damage repair, NGCs help prevents the build-up of scar tissue because the nerves repair themselves more efficiently.

Current methods of surgery involve grafting a nerve from one part of the body and transplanting it into the traumatised area but this means the section from which the nerve is grafted can suffer nerve-damage symptoms.

The NGC technique of 3D engineering was developed at the University’s Faculty of Engineering using computer-aided design.

The device, which is essentially a tube, has a wall thickness of around 100 to 250 microns - up to 2.5 times the width of a human hair - and a diameter of about 1mm.

Researchers used the NGCs with nerve injuries in a mouse model and were able to demonstrate a successful repair of an injury gap of 3mm in a 21-day period.

John Haycock, Professor of Bioengineering, said: "We've shown that this works in animal models, so the next step is to take this technique towards the clinic."

Dr Frederik Claeyssens, Senior Lecturer in Biomaterials, said: “With 3D printing we can produce tubes that fit into the body perfectly. It will help the body regenerate naturally and because it is made with biodegradable materials it will simply disintegrate, working much like a dissolvable stitch.”

The material used for NGCs is polyethylene glycol, which is already cleared for clinical use and suitable for use in 3D printing.

The next step is to test the process on larger gaps between nerves, as Dr Claeyssens explains.

"We want to work on bridging gaps that are more critical, more than 2cm long. This length of gap presents problems even with current methods of nerve grafting. We are aiming for a solution to this problem that will go beyond gold standard practice."

The implications for 3D printing in medical applications are huge. "This is just the start," says Dr Frederik Claeyssens. "3D printing in healthcare could become so important. Nerves are just one example, we are also looking at other tissues as potential for applying this technology."

He says: "What we are achieving now is seriously advancing the application of 3D printing."