Repairing Spinal Cord Injuries with 3D-Printed Scaffolds
Repairing Spinal Cord Injuries with 3D-Printed Scaffolds
Researchers at the University of Minnesota are using 3D-printed scaffolds to promote stem cell growth, paving the way for new spinal cord injury treatments and potential mobility restoration.
When Guebum Han first embarked on his studies in mechanical engineering, he thought he’d likely use his education and skills in machines or motion. Instead, the former University of Minnesota (UMN) mechanical engineering postdoctoral researcher, who now works at Intel Corporation, is making strides on new therapies to treat human spinal cord injuries.
More than 300,000 people in the United States alone currently live with spinal cord injuries, with about 18,000 new cases occuring each year, according to the National Spinal Cord Injury Statistical Center. While spinal cord damage is largely permanent, as no existing therapies offer a way to reverse such injuries, Han is working on new research with UNM Twin Cities’s Parr Laboratory that could change that.
“The reason I wanted to join this lab was because of this project,” Han said.
Through a process that combines 3D printing, stem cell biology, and lab-grown tissues, this team has developed an organoid scaffold—a 3D-printed framework for lab-grown organs—that features microscopic channels populated with regionally specific spinal neural progenitor cells (sNPCs), which originate from human adult stem cells. This solution might just make recovery from spinal cord injuries possible.
Han’s previous experience with 3D printing included research into the pick and placement of live organisms, which he now brings to the research team led by UMN Neurosurgery Professor Ann Parr. The project aims to develop 3D printing technologies that can help direct the growth of lab grown stem cell tissues to better mend damaged spinal cords.
“The idea that I’m using mechanical engineering to solve some medical challenges was really inspiring to me,” said Han, who is the first author of the study recently published in Advanced Healthcare Materials.
Han said using mechanical engineering to serve as enabling technology is a perfect fit with the medical field’s goals to improve the quality of life of patients with spinal cord injuries.
Relevant Reads: Rebooting the Spinal Cord
Just a few months after he started working on the development of the 3D-printed scaffolds, Han’s in-laws were involved in a serious car accident. While his father-in-law recovered, his mother-in-law suffered severe injuries that affected her organs and limited any movement below her neck.
Sadly, she passed away a few months later. The event made Han even more dedicated to seeing the scaffolding project through and advancing a solution that could help other people.
“I know it’s going to be a small step in the whole field when I think of the next 20 years, but it’s a very meaningful step,” Han said.
The UNM team’s work builds upon previous research on neural regeneration by creating 3D-printed scaffolds that include channels and can bridge the length of a spinal cord injury.
“The printing loader comes and then dispenses live stem cells in the channels,” he explained.
One way the team advanced on the previous research was to extend the stem cell growth observation period, first to 40 days, and then to an entire year.
Those distributed cells are like “baby neurons” being grown in an incubator that continually develop into fully matured neurons, Han explained. They eventually form the organoid, which is considered a biological system—the closest system to body tissue, which consists of multi cells and behaves much like actual tissue.
After seeing how the scaffold was able to help the organoid grow in the proper directions via the channels and develop into larger tissue over the ends of the scaffold, the team felt it was time to test it out.
“Now we know how to print it, and we know how to create the organoid, what if we transplant this into the animal directly?” Han presented.
The team used rats with severed spines for their control and experimental groups. Immediately after the scaffolded cells were implemented in the experimental rat group, they were unable to move their bodies below the injury, similar to the control group that did not receive any treatment.
But after 12 weeks, members of the control group could only continue to drag their legs. The rats in the experimental group showed marked improvement as the implanted scaffolds and nerve cells integrated into the host’s spinal cord tissue.
“It’s not perfect, but [in the video] you can see the leg can hold the load and then try to kick it again—a pretty amazing difference, really,” Han said.
This 3D printing technology is ideal for creating customized 3D shapes to bridge the injury area.
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“We were able to match exactly the damage area as it related to the length,” he said.
The 3D scaffold and cell development work is similar to approaches used in other biomedical engineering applications to replace cartilage or bone.
As the work advances, Han believes his team will be able to create any complex architecture with the prints that exactly match the damage and then replace them.
Of course, a rat’s spinal cord is much smaller than that of a human, so there are challenges to scaling up. Also complicating the ability to bring the technology to human clinical scenarios are instances when a human’s spinal cord is only partially damaged.
One of the challenges Han foresees with scaling up to human use is how to print such large amounts of tissue, which takes more time to ensure it can be done without degrading the quality of the scaffold and cells. Magnetic resonance imaging and scanning technology is key.
“If we have the image information, then we can change the printing code and mechanical engineers can work on how we can create that scaffold with soft material, maintaining structural integrity and seeding the cells into the scaffold, and then transplant the customized scaffold into the damaged area,” he said.
Nancy Kristof is a technology writer in Denver.
More than 300,000 people in the United States alone currently live with spinal cord injuries, with about 18,000 new cases occuring each year, according to the National Spinal Cord Injury Statistical Center. While spinal cord damage is largely permanent, as no existing therapies offer a way to reverse such injuries, Han is working on new research with UNM Twin Cities’s Parr Laboratory that could change that.
“The reason I wanted to join this lab was because of this project,” Han said.
Through a process that combines 3D printing, stem cell biology, and lab-grown tissues, this team has developed an organoid scaffold—a 3D-printed framework for lab-grown organs—that features microscopic channels populated with regionally specific spinal neural progenitor cells (sNPCs), which originate from human adult stem cells. This solution might just make recovery from spinal cord injuries possible.
A personal mission
Han’s previous experience with 3D printing included research into the pick and placement of live organisms, which he now brings to the research team led by UMN Neurosurgery Professor Ann Parr. The project aims to develop 3D printing technologies that can help direct the growth of lab grown stem cell tissues to better mend damaged spinal cords.
“The idea that I’m using mechanical engineering to solve some medical challenges was really inspiring to me,” said Han, who is the first author of the study recently published in Advanced Healthcare Materials.
Han said using mechanical engineering to serve as enabling technology is a perfect fit with the medical field’s goals to improve the quality of life of patients with spinal cord injuries.
Relevant Reads: Rebooting the Spinal Cord
Just a few months after he started working on the development of the 3D-printed scaffolds, Han’s in-laws were involved in a serious car accident. While his father-in-law recovered, his mother-in-law suffered severe injuries that affected her organs and limited any movement below her neck.
Sadly, she passed away a few months later. The event made Han even more dedicated to seeing the scaffolding project through and advancing a solution that could help other people.
“I know it’s going to be a small step in the whole field when I think of the next 20 years, but it’s a very meaningful step,” Han said.
Bridge-building
The UNM team’s work builds upon previous research on neural regeneration by creating 3D-printed scaffolds that include channels and can bridge the length of a spinal cord injury.
“The printing loader comes and then dispenses live stem cells in the channels,” he explained.
One way the team advanced on the previous research was to extend the stem cell growth observation period, first to 40 days, and then to an entire year.
Those distributed cells are like “baby neurons” being grown in an incubator that continually develop into fully matured neurons, Han explained. They eventually form the organoid, which is considered a biological system—the closest system to body tissue, which consists of multi cells and behaves much like actual tissue.
After seeing how the scaffold was able to help the organoid grow in the proper directions via the channels and develop into larger tissue over the ends of the scaffold, the team felt it was time to test it out.
“Now we know how to print it, and we know how to create the organoid, what if we transplant this into the animal directly?” Han presented.
The team used rats with severed spines for their control and experimental groups. Immediately after the scaffolded cells were implemented in the experimental rat group, they were unable to move their bodies below the injury, similar to the control group that did not receive any treatment.
But after 12 weeks, members of the control group could only continue to drag their legs. The rats in the experimental group showed marked improvement as the implanted scaffolds and nerve cells integrated into the host’s spinal cord tissue.
“It’s not perfect, but [in the video] you can see the leg can hold the load and then try to kick it again—a pretty amazing difference, really,” Han said.
This 3D printing technology is ideal for creating customized 3D shapes to bridge the injury area.
Discover the Benefits of ASME Membership
“We were able to match exactly the damage area as it related to the length,” he said.
The 3D scaffold and cell development work is similar to approaches used in other biomedical engineering applications to replace cartilage or bone.
As the work advances, Han believes his team will be able to create any complex architecture with the prints that exactly match the damage and then replace them.
Of course, a rat’s spinal cord is much smaller than that of a human, so there are challenges to scaling up. Also complicating the ability to bring the technology to human clinical scenarios are instances when a human’s spinal cord is only partially damaged.
One of the challenges Han foresees with scaling up to human use is how to print such large amounts of tissue, which takes more time to ensure it can be done without degrading the quality of the scaffold and cells. Magnetic resonance imaging and scanning technology is key.
“If we have the image information, then we can change the printing code and mechanical engineers can work on how we can create that scaffold with soft material, maintaining structural integrity and seeding the cells into the scaffold, and then transplant the customized scaffold into the damaged area,” he said.
Nancy Kristof is a technology writer in Denver.
