Muscle tissue from a 3D printer – produced in zero gravity

On their way into space, astronauts' bodies deteriorate dramatically in zero gravity. To address this problem and protect our pioneers in space, researchers are looking for realistic test models.

This is precisely where the research of a team at ETH Zurich comes in. To produce muscle tissue under the most precise conditions possible, the research team led by Parth Chansoria used parabolic flights to simulate the microgravity of space for a short period of time. This technical feat brings the researchers closer to their long-term goal: growing human tissue in orbit to study diseases and develop new therapies.

Why manufacture in zero gravity?

The production of fine, biological structures such as muscle tissue poses a major challenge under normal gravitational conditions on Earth. The goal is to print tissue that looks exactly like the natural structures in the body. However, gravity interferes with the process.

For 3D printing, researchers use a special substance called bio-ink. This consists of a carrier material mixed with living cells. The weight of the bio-ink and the embedded cells can cause the structures to collapse or deform before the material can harden. In addition, the cells can sink unevenly in the bio-ink. This leads to less realistic models.

Under microgravity, these disruptive forces disappear. Without structural stress, researchers can produce muscle fibers exactly as they are aligned in the body. This precise construction is crucial: only models that accurately reflect the human body structure provide reliable results when testing new drugs or studying disease progression.

A new gravity-independent system

To this end, the ETH researchers developed a new biofabrication system called G-FLight (Gravity-independent Filamented Light). This system enables the rapid production of viable muscle constructs within seconds.

Using a special bio-resin formulation, the team performed 3D printing during the weightless phases of 30 parabolic cycles. The results showed that the tissue printed in microgravity had similar cell viability and a similar number of muscle fibers than the tissue printed under gravity. In addition, the developed process enables long-term storage of the cell-loaded bio-resins, which is ideal for future applications in space.

Disease models beyond earth

The successful production of muscle constructs in microgravity represents an important advance for tissue engineering in space research and biomedicine. The aim is to use these techniques to produce complex human organoids and tissues on board the International Space Station or future orbital platforms. In space, researchers can conduct basic research thanks to these ‘organ models’: They are used to study diseases such as muscular dystrophy or muscle atrophy caused by weightlessness. In addition, they can be used to test the effectiveness of therapeutics in a system that better reflects the complexity of the human body – because 3D printing in weightlessness allows muscle fibers to be aligned with such precision and accuracy.