Implantable 3D printed device could improve spinal cord injury treatment

Though spinal cord injuries can be a life changing issue—resulting discomfort, extreme pain and even paralysis—new 3D printing research coming from the University of Minnesota could take us one step closer to treating and helping people with long-term spinal cord injuries.

A team of engineers and medical researchers from the university have jointly developed a 3D printed device which could be implanted into the spinal cord and act as a “bridge,” connecting healthy nerve cells above and below the injury. The innovative medical device consists of a 3D printed silicone scaffold which can have specialized cells bioprinted onto it.

The potentially life-changing development, recently published in the journal Advanced Functional Materials, aims to help patients with long-term spinal cord injuries by lessening pain and by regaining certain functions affected by the injury, including muscle, bowel and bladder control.

“This is the first time anyone has been able to directly 3D print neuronal stem cells derived from adult human cells on a 3D printed guide and have the cells differentiate into active nerve cells in the lab,” commented Michael McAlpine, Ph.D., a co-author of the study and associate professor  of Mechanical Engineering at the university’s College of Science and Engineering.

Considering there are roughly 285,000 people in the U.S. alone who have spinal cord injuries, and with more occurring on a too frequent basis, having a suitable treatment to help people could be game-changing in the medical field.

Ann Parr, M.D., Ph.D, and assistant professor in the Department of Neurosurgery and Stem Cell Institute, elaborated: “This is a very exciting first step in developing a treatment to help people with spinal cord injuries. Currently, there aren’t any good, precise treatments for those with long-term spinal cord injuries.”

The 3D printed spinal device begins with a series of adult cells, whether skin cell, blood cell or other. Using bioengineering processes, the medical researchers can essentially reprogram these cells to be neuronal stem cells.

From there, the engineers worked with a specialized 3D printing technology to deposit layers of silicone, created a guide for the cells. The 3D printer they used was able to alternate between silicone deposition and the cell deposition. According to the researchers, the silicone guide encases the bioprinted cells and provides an environment that both keeps them alive and enables them to transform into neurons.

After two years working on the research project, the team now has a prototype guide which could be implanted into a damaged spinal cord to provide a connection between the living cells on either side of the injury.

Though the process sounds remarkably straightforward, developing the spinal cord guide did come with its challenges. As McAlpine explains: “3D printing such delicate cells was very difficult. The hard part is keeping the cells happy and alive. We tested several different recipes in the printing process. The fact that we were able to keep about 75 percent of the cells alive during the 3D-printing process and then have them turn into healthy neurons is pretty amazing.”

Now, however, after much hard work and perseverance, things are falling into place for the University of Minnesota team. The hope that the next stages in their research will prove that the 3D printed devices could have real-world applications and help those suffering from spinal injuries.

“We’ve found that relaying any signals across the injury could improve functions for the patients,” Parr said. “There’s a perception that people with spinal cord injuries will only be happy if they can walk again. In reality, most want simple things like bladder control or to be able to stop uncontrollable movements of their legs. These simple improvements in function could greatly improve their lives.”