The International Space Station (ISS)’s first long-term crew arrived on November 2, 2000. Since then, we’ve become familiar with many of the astronauts’ projects: growing plants, testing the health effects of long-term spaceflight, growing crystals and building new equipment and spacewalks.
But 3D bioprinting human organs? Yep, that’s a new experiment. And the Wake Forest Institute for Regenerative Medicine (WFIRM) in Winston-Salem oversees it.
“Sending our projects to the International Space Station is truly the next frontier for us in terms of the work that we do,” said Dr. Anthony Atala, director of WFIRM, in a NASA video about the mission.
Bioprinting allows scientists to create intricate three-dimensional structures using living human cells to build working replicas of human tissues and organs. Think 3D printing but with human cells rather than plastics. And because the tissues are made with human cells, the chance of the body rejecting the organ is greatly reduced. Engineered tissues can be used to study disease or repair damaged tissues.
The focus in this experiment is the liver, which is crucial to human health. The liver filters toxins and harmful substances from the blood, including drugs and alcohol. It converts them into less harmful compounds that are then excreted from the body.
The liver also plays an important role in metabolizing carbohydrates, fats and proteins.
Researchers at WFIRM have successfully engineered liver tissues in the lab that have survived for 30 days. But it turns out that 3D bioprinting a liver creates a special challenge.
Think of the functions that the liver performs. The organ needs a lot of blood, and thus blood vessels, to stay healthy. And with the gravity on Earth, it’s difficult to bioprint and maintain tissues with a lot of blood vessels (called “vascularized tissue”). Engineered organs with limited vascularization have a difficult time getting oxygen and nutrients while removing waste from the body.
Researchers want to see if the microgravity on the space station changes cell distribution and behavior and how the cells stick together. The theory is that with less gravity, the cells will grow omnidirectionally (in all directions) and thus more evenly. That would help preserve the integrity of the 3D-printed organ and its blood vessels. This could provide insight into how to advance tissue engineering and manufacture better, longer-lasting tissues for disease research and patients on Earth.
“By having those conditions in space, they would give us much better insight into how cells work, function and how to make them better,” Atala added in the video.
“This collaborative investigation has the potential to yield remarkable results,” said James Yoo, a professor at WFIRM who is leading the study, in a release from the ISS National Lab. “By leveraging bioprinting technologies, we’ve created gel-like frameworks with channels for oxygen and nutrient flow that mimic natural blood vessels, opening up new possibilities for medical treatments both on Earth and in space.”
The project gained NASA’s attention after two teams of researchers from WFIRM used 3D printing technologies to create tissue constructs as part of NASA’s Vascular Tissue Challenge. The competition, which ran from 2016 to 2021, was aimed at utilizing the ISS National Lab to speed up tissue engineering innovations and regenerative medicine technologies, which would help humans exploring space as well as those on Earth. The teams worked to produce functional tissue that would remain viable outside the body for a month or more. The two teams won a total of $400,000 to help fund their research. But the big prize is that both teams will get the opportunity to test their technology on the ISS itself.
The experiments arrived on a SpaceX resupply mission to the ISS at the end of August 2025. Testing will last for several months, with the tissues returned to Earth for analysis by the end of the year.
We visited WFIRM researchers in 2018, the early days of their work. To learn more about WFIRM, watch this Sci NC story.