ETH Zurich 3D Prints Human Muscle in Microgravity

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.