Researchers Regenerate Complex Nerves Using 3D Printing Technology

A team of researchers from the University of Minnesota, Virginia Tech, University of Maryland, Princeton University and Johns Hopkins University have created a new kind of 3D-printed guide capable of assisting complex motor and sensory nerves to re-grow subsequent to an injury.

This research could have a major impact in the medical field by serving numerous patients suffering from nerve disease or injuries.

Nerve regeneration is a huge challenge. According to the Mayo Clinic, due to the complexities involved, nerve re-growth post injury or disease is very uncommon. It is also widely thought that damage to nerves is mostly permanent. The solution to these challenges lies in innovative 3D printing techniques.

A paper, published online in the Advanced Functional Materials journal, illustrates a combination of 3D printing and 3D imaging methods used to build custom silicone guide, which can then be implanted using biochemical cues to assist the re-growth of nerves. Laboratory testing on rats confirmed the effectiveness of this guide.

Using a 3D scanner, the researchers reverse engineered the sciatic nerve structure of a rat. Next, using an advanced, custom-built 3D printer, a guide was printed for regeneration. 3D-printed chemical cues were added to the guide to support the regeneration of sensory and motor nerves. Finally, the guide was surgically implanted in the rat by grafting it to the cut nerve ends. The rat regained its ability to walk again within a span of three months.

"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."

Although the scanning and printing activities take only an hour, the physical body would require more than a couple of weeks for the nerves to be regenerated.

McAlpine stated that even though earlier researches have illustrated linear nerve regeneration, this would be the first time where a custom guide was developed for use in complex nerve regeneration such as a Y-shaped sciatic nerve comprising both motor and sensory functions.

"The exciting next step would be to implant these guides in humans rather than rats," McAlpine said.

Going forward, McAlpine suggests that if a nerve is not available for scanning, a "library" of scanned nerves from other patients or cadavers can be formed, which could be utilized by hospitals to build a closely corresponding 3D-printed guide for patients.