University of Minnesota reports breakthrough in 3-D printing for spinal cord repair

Star Tribune, August 9, 2018

University of Minnesota researchers have broken new ground in the rapidly advancing field of 3-D printing: creating stem cell-infused scaffolds that could be implanted in spinal cords to repair nerve damage.

The technology has existed for years to print plastic implants containing live cells. But the challenge was to do so in a way that would allow sensitive “neuronal” stem cells to survive the printing process so they can repair nerve damage after transplant.

“No one has been able to print those stem cells where they differentiate into active nerve cells using a 3-D printer,” said Michael McAlpine, a U mechanical engineer who teamed up with Dr. Ann Parr, a neurosurgeon, to lead the research. “The cells have to survive the printing process.”

The team on Thursday reported a printing approach that allowed for 75 percent survival of neural progenitor cells, which are limited stem cells capable of producing brain cells. Results were published in Advanced Functional Materials, a prestigious technical journal. A university video demonstrates how the soft rubbery scaffold could be printed in layers along with hydrogel, a special ink that coats and preserves the stem cells.

“You need to have something around the cells so that when they are printed they are happy — basically, they stay alive,” McAlpine said.

Use of the technology in regenerative medicine for human patients remains some years away: The printed scaffolds have to be tested in animals to see if they repair spinal cord damage, and then human tests would follow.

The discovery is one in a series involving 3-D printing, which was initially used in health care to create models for surgery practice, but now is being studied for the creation of everything from skin grafts to solid organs for transplant.