Regenerating nerves is a complex—and usually impossible—process, but a new study published in Advanced Functional Materials shows the potential to heal nerve damage using one of the most versatile inventions of our time: 3D printing.
Outside of the central nervous system, hundreds of neural “telephone wires” known as axons travel long distances in the body together, in bundles known as nerves. Naturally, damaging this bundle often results in permanent damage to the body, because reconnecting hundreds of microscopic cells is generally impossible. In the course of one year, 200,000 Americans will experience nerve injuries or disease; many will never fully recover.
But a collaboration between the University of Minnesota, Virginia Tech, the University of Maryland, Princeton University, and Johns Hopkins University has successfully managed to combine 3D imaging with 3D printing has created a sort of cast for nerve bundles that helps them to reconnect and heal.
Scanning and printing
The researchers first scanned the shape of rats’ sciatic nerves—the Y-shaped bundles responsible for feeling and moving the legs of both rats and humans. From this scan, they created a silicone guide imbued with biochemical signals for nerve regeneration. The nerves were cut, leaving the rats unable to walk or feel their legs.
The guides were surgically implanted, with the nerve endings grafted inside. After 10 to 12 weeks, the rats’ ability to walk had improved—whereas normally, they would have remained paralyzed.
“This represents an important proof of concept of the 3D printing of custom nerve guides for the regeneration of complex nerve injuries,” said University of Minnesota mechanical engineering professor Michael McAlpine, the study’s lead researcher. “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.”
Previous studies have regrown nerves before, but never anything as complex as the sciatic nerve—which has both sensory (“feeling”) and motor (“moving”) branches. The custom guide is unique as well, and scanning the nerve shape and printing the cast takes only about an hour. In the future, McAlpine believes medical practitioners cold create a library if scanned nerves to speed up this process. Of course, another important move must be made before that can happen.
“The exciting next step would be to implant these guides in humans rather than rats,” McAlpine said.
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Image credit: Thinkstock
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