While bioprinting usually takes place in controlled Earth-based labs, researchers at ETH Zurich have taken the technology to new heights, quite literally. In a new experiment, the Swiss team successfully 3D printed human muscle tissue during parabolic flights that simulate the weightlessness of space. Previous experiments aboard the International Space Station (ISS) have demonstrated 3D printing of polymers, cartilage, and even vascular tissues, but never human skeletal muscle.
The work builds on earlier efforts to print biological materials in microgravity, expanding the potential of space-based biomanufacturing. By focusing on living muscle tissue, the ETH Zurich team brings new precision to tissue modeling for drug testing, disease research, and potentially long-term astronaut healthcare. Because muscle degradation is one of the most severe effects of extended spaceflight, creating accurate muscle models is essential for studying and mitigating this loss. Published in Advanced Science, the study showcases how the accuracy of 3D bioprinting improves once gravity is removed from the equation.
Diagram of the G-FLight bioprinting system and workflow, showing laser-based printing of bioresins and the experimental process used during parabolic flight. (Photo credit: ETH Zurich)
Why Print in Zero Gravity
Recreating the complexity of human tissue with 3D printing has always been limited by one persistent factor: gravity. On Earth, soft bio-inks made of hydrogels packed with living cells tend to collapse or deform before solidifying, which compromises the accuracy of the printed structure. Cells can also settle unevenly during printing, reducing the biological realism of the resulting tissue. Microgravity changes that.
“Our system, G-FLight, together with the novel biomaterial inks to encapsulate cells, can produce biomimetic muscle constructs in seconds. This system is also not affected by gravity, where the tissues printed in zero gravity aboard parabolic flights mimic the properties of those printed in Earth’s gravity, enabling a predictability of tissue properties,” says Parth Chansoria, who led the study. This ability to precisely replicate muscle architecture is critical for biomedical research, where even subtle structural variations can alter how diseases progress or how drugs perform in human tissue.
Introducing G-FLight: A Gravity-Free Bioprinting System
To achieve this feat, ETH Zurich designed its own microgravity-capable bioprinter called G-FLight (Gravity-independent Filamented Light). During 30 parabolic flight cycles, each creating around 20 seconds of weightlessness, the system printed viable muscle constructs in midair using a custom bio-resin infused with living muscle cells.
G-FLight 3D bioprinter and example constructs, including the ETH logo, cylinders, and sheets, printed in microgravity with visible microfilament detail. (Photo credit: ETH Zurich)
Despite being produced under extreme conditions, the microgravity-printed fibers showed comparable cell viability and density to ground-based samples but with improved structural integrity thanks to the absence of gravitational deformation.
The team also demonstrated that bio-resins could be stably stored and later activated in flight, a critical feature for future missions involving long-term space processing.
Toward Space-Based Tissue Engineering
3D printing muscle tissue in microgravity is not just a niche scientific achievement. It could reshape how we study, repair, and even manufacture biological systems in space.
The next step for ETH Zurich is to take the research beyond the “vomit comet” and into orbit. The goal is to fabricate complex organoids aboard the ISS or future commercial platforms. These lab-grown tissues could be used to study conditions such as muscle atrophy induced by spaceflight or diseases like muscular dystrophy, without the interference of Earth’s gravitational pull.
A Growing Field of Space Bioprinting
ETH Zurich’s work builds on a growing body of research focused on advancing bioprinting beyond Earth’s surface. Earlier this year, Redwire Space announced the successful bioprinting of a human knee meniscus aboard the ISS. Meanwhile, Wake Forest’s Institute for Regenerative Medicine sent 3D printed liver tissue to space to study organ development under microgravity.
Although applications remain in their early stages, ETH Zurich’s achievement represents a key step forward in the effort to develop reliable bioprinting systems for space environments. The research underscores how additive manufacturing could one day support both scientific discovery and long-term human health beyond our planet. You can find out more in the official press release from ETH Zurich HERE. Now, that’s one small step for man, one giant leap for space-based tissue engineering.
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*Cover Photo: Researchers led by Parth Chansoria performed parabolic flight experiments simulating microgravity to 3D print muscle tissue. (Photo Credit: ETH Zurich)