Collaborators on the project are from the University of Minnesota, Virginia Tech, University of Maryland, Princeton University, and Johns Hopkins University.
Nerve regeneration is a complex process. Because of this complexity, re-growth of nerves after injury or disease is very rare, according to the Mayo Clinic. Nerve damage is often permanent. Advanced 3D printing methods may now be the solution.
The researchers used a combination of 3D imaging and 3D printing techniques to create a custom silicone guide implanted with biochemical cues to help nerve regeneration. The guide's effectiveness was tested in the lab using rats.
A 3D scanner was used to reverse engineer the structure of a rat's sciatic nerve. The researchers then used a custom-built 3D printer to print a guide for regeneration. Incorporated into the guide were 3D-printed chemical cues to promote both motor and sensory nerve regeneration. The guide was then implanted into the rat by surgically grafting it to the cut ends of the nerve. Within about 10 to 12 weeks, the rat's ability to walk again was improved.
Professor Michael McAlpine the study's lead researcher, said: "Someday we hope that we could have a 3D scanner and printer right at the hospital to create custom nerve guides right on site to restore nerve function."
Scanning and printing takes about an hour, but the body needs several weeks to re-grow the nerves. Prof McAlpine said previous studies have shown re-growth of linear nerves, but this is the first time a study has shown the creation of a custom guide for re-growth of a complex nerve like the Y-shaped sciatic nerve that has both sensory and motor branches.
"The exciting next step would be to implant these guides in humans rather than rats," Prof McAlpine said. In cases where a nerve is unavailable for scanning, there could someday be a ‘library’ of nerves scanned from other people that hospitals could use to create closely matched 3D-printed guides for patients.
