The New Frontier of Science: Manufacturing Human Tissue in Space

Scientists are developing a new technology that allows them to "print" human tissues in space. This technique could help astronauts on long missions by creating muscles or skin on demand, and also contribute to new medical treatments on Earth.

The space race, which took place between the 1950s and 1970s, was one of the most exciting periods in human history. At that time, countries like the United States and the Soviet Union competed to conquer space, leading to an explosion of scientific and technological innovations.

Even though manned missions have decreased in the following decades, the dream of exploring other planets has never disappeared. Today, thanks to advances in computers and the creation of reusable rockets, traveling and working in space is becoming increasingly possible and economical.

However, sending humans into space for extended periods presents significant challenges. The human body changes considerably in a zero-gravity environment. For example, muscles and bones can weaken, and the organism undergoes transformations that are not yet fully understood.

Furthermore, if a person were to suffer a serious injury or require a transplant during a mission, it would be necessary to have a way to repair or regenerate human tissue right there, without relying on a hospital on Earth. This is where an innovative field of science called biofabrication comes in, which is the creation of biological tissues in the laboratory.

There are two main ways to perform biofabrication in a space context. The first is to produce tissues directly in space, taking advantage of the microgravity environment. The second is to create the tissues on Earth and send them ready-made into space to mature there.

Doing everything on Earth is simpler, but manufacturing tissues directly in space offers a huge advantage: it's possible to produce customized structures, adapted to each person and the specific conditions of the space environment.

Currently, most biofabrication experiments in space use a technique called extrusion printing, which works similarly to a 3D printer, but using cells and biomaterials. With this technique, it has already been possible to manufacture simple tissues, such as parts of bones, menisci, and skin, using small printers carried aboard missions.

The absence of gravity helps a lot, as materials can be deposited freely, forming complex three-dimensional structures without needing support.

Despite these advances, there are still significant challenges. Tissues such as muscles, nerves, and the heart, called anisotropic tissues because their fibers are aligned in a specific direction, are very difficult to reproduce. In space, the models created so far fail to properly orient the cells, preventing the tissue from developing functionally.

G-FLight printer and examples of microfilament structure prints. A) Components of the G-FLight printer contained in a volume of 30 (length) × 45 (width) × 30 (height) cm. B) The assembled G-FLight printer and its main components used during the microgravity printing phase. C) Examples of prints of the ETH logo, cylindrical and blade-shaped structures using rhodamine-labeled resins (red).

Therefore, experiments with muscle tissue in space are still done in simple versions, grown inside special chambers. Even so, these experiments have been valuable, as they help scientists better understand diseases such as muscle wasting that occurs in astronauts.

To solve these problems, a group of researchers developed a new technique called FLight, which uses light beams (such as lasers) to manufacture tissues with precisely aligned structures. This light creates microfilaments within a special resin, forming a network similar to the natural tissue of the human body. Based on this idea, an advanced version of the technology called G-FLight was created, designed to work even in zero-gravity environments. This printer is compact, vibration-resistant, and suitable for use inside aircraft and, in the future, in space stations.

Scientists tested the G-FLight system in parabolic flights, aircraft that simulate brief periods of weightlessness, about 20 seconds each. During these intervals, they were able to manufacture tissues in seconds, showing that the method is viable. To do this, they also needed to create new biological resins (called bioresins) that contain living cells and can be stored in a practical and safe way.

To create precise muscle tissue, Dr. Parth Chansoria's team used parabolic flights to simulate microgravity. Source: ETH Zurich / Wiley Online Library

Conventional resins require a great deal of care and training to be used in space. Therefore, the group developed two new versions called CoolResin and CryoResin. The first can be stored in a refrigerator, and the second can be frozen at very low temperatures. Both keep cells alive for days or weeks inside small sealed containers. At the time of printing, simply thaw the material and start the process.

These new resins are based on a biological material called gelatin methacrylate, widely used in tissue engineering. Tests were conducted between laboratories in Switzerland and flight centers in France.

Samples were printed both on Earth and in microgravity to compare the results. After printing, the tissues were cultured and analyzed for cell viability, multiplication capacity, and maturation.

Bioprinted muscle fibers in microgravity. With the formation of myotubes after 17 days in culture (1 week of growth + 10 days of differentiation), it is possible to identify the myosin (green) and actin (red) proteins; the nucleus of all cells appears in blue.

The results showed that the tissues created in space with the new resins had healthier and more organized cells, forming muscle structures similar to those produced on Earth. This is important because it shows that the technique works equally well outside of Earth, which is a fundamental step for the future of space medicine.

This research paves the way for a future in which human organs and tissues can be manufactured in space, whether to treat astronauts on long-duration missions or to develop new therapies on Earth. The G-FLight technology and the new resins represent a promising advance towards biofabrication in extraterrestrial environments, one of the next great challenges of modern science.

READ MORE:

Prolonged Cell Encapsulation and Gravity-independent Filamented Light Biofabrication of Muscle Constructs

Michael Winkelbauer, Jakub Janiak, Johannes Windisch, Hao Liu, Maria Bulatova, Max Von Witzleben, Hugo Oliveira, Sophie Dani, Richard Frank Richter, Nicolas L’Heureux, Ori Bar-Nur, Michael Gelinsky, Marcy Zenobi-Wong, and Parth Chansoria 

Advanced Science. 23 September 2025 

https://doi.org/10.1002/advs.202512727

Abstract:

The prospects of fabricating human tissue grafts or models using cell-laden bioresins in space have garnered significant interest in recent years. While there is tremendous progress in extrusion or light-based bioprinting in microgravity conditions, printing of aligned tissues (e.g., muscle, tendon, cardiac, etc.) remains a challenge. Furthermore, current photoresin formulations do not allow long-term cell encapsulation and are difficult to handle in microgravity conditions. In this study, a new gravity-independent filamented light (G-FLight) biofabrication system, which can create viable muscle constructs within seconds, is demonstrated. New photoresin formulations based on gelatin methacrylate (GelMA) for encapsulation of primary cells (murine myoblasts) and storage in printing cuvettes for at least a week at 4 °C or -80 °C are also demonstrated. The tissues printed in microgravity based on the new formulations exhibit higher cell viability, number of proliferating cells, and higher numbers of myotubes and fusion index compared to control formulations (i.e., GelMA dissolved in phosphate-buffered saline). Importantly, the microgravity-printed tissues also featured similar myotube density and fusion index to those printed using the same resins on-ground. The G-Flight printing concept, together with the new resins enabling refrigeration or cryopreservation with encapsulated cells, offers a promising solution for biofabrication in space.