Preserved at -80℃ In-Orbit for 6 Months, How Does Space Medicine Rewrite the Rules of Regenerative Medicine?

On April 30, 2025, the Shenzhou-19 manned spaceship successfully landed at the Dongfeng Landing Site. In addition to the 3 astronauts, a special "cargo"—human pluripotent stem cell samples preserved in-orbit for 6 months—also returned to Earth safely.

These stem cells, which completed 3D growth experiments in the -80℃ environment of the space station, mark China's first technological breakthrough in the long-term cryopreservation and automated culture of stem cells in space, opening up a new dimension for space medicine and regenerative medicine research. Led by the team of Researcher Lei Xiaohua from the Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences, this achievement represents a major milestone in China's space life sciences field.

A Revolution in Stem Cell Culture Under Microgravity

The primary challenge for Lei Xiaohua's team was achieving the orderly growth of stem cells in a microgravity environment. In the microgravity of space, traditional cell culture is prone to suspension disorders and uneven differentiation. 

To address this issue, the research team modified a dedicated cell culture chamber, constructed 3D cell culture channels using PDMS (polydimethylsiloxane) material, and designed a microfluidic chip-based growth scaffold with channel dimensions precisely controlled between 50-200 micrometers. This enabled stem cells to grow in an orderly 3D cluster in space, forming a stereoscopic structure similar to that of tissues and organs.

A more critical breakthrough lies in the in-orbit long-term preservation technology. Since the space station cannot provide the liquid nitrogen environment available in ground laboratories, researchers screened cryoprotectants suitable for the space environment, innovatively using components such as self-assembling polypeptides, galactose, and sorbitol, and added small-molecule compounds to inhibit cell apoptosis. 

This specially formulated cryoprotectant forms a bowl-shaped core-shell particle structure, preventing water from entering cells while allowing excess organic solvents to diffuse out, thereby reducing damage to cell membranes caused by ice crystals during cryopreservation. Combined with the space station's -80℃ cryogenic refrigerator, the survival rate of stem cells remained above 85% after 6 months of cryopreservation—three times longer than the preservation duration of similar experiments on the International Space Station (ISS).

During the in-orbit period, the experimental device recorded the growth status of stem cells in real time via an automated microscopic imaging system. 

The transmitted images showed that the proliferation rate of space-grown stem cells was 17% faster than that of ground-grown ones, with tighter intercellular connections. This provides a new basis for studying the impact of microgravity on cell communication. Researcher Lei Xiaohua stated, "This discovery has overturned our understanding of the survival mechanisms of stem cells in extreme environments."

The Value Leap from Astronaut Health to Ground-Based Medicine

This research achievement holds dual milestone significance for space exploration and ground-based medicine. During long-duration space missions, astronauts face health challenges such as osteoporosis and muscle atrophy. The phenomenon of enhanced "stemness" (pluripotency and self-renewal ability) of stem cells observed in this experiment has laid the foundation for the development of in-orbit regenerative therapies.

The research team observed a significant increase in the concentration of neurotrophic factors secreted by space-grown stem cells—a finding that opens up a new direction for the research and treatment of neurodegenerative diseases such as Alzheimer's disease. 

Meanwhile, the unique state of stem cells in microgravity may help develop new methods to counteract weightlessness-induced bone loss. Similar research has been validated in zebrafish experiments, where the knockout of specific genes was found to counteract bone loss and myocardial remodeling.

In the field of space-based pharmaceutical research, simultaneous experiments showed that the efficiency of drug uptake by cells in a microgravity environment increased by 40%. 

This means that in the future, it will be possible to rapidly screen high-efficiency drugs on the space station and even produce special biological agents that are difficult to synthesize on the ground. Lei Xiaohua noted, "The microgravity environment in space is like a natural bioreactor, providing us with research conditions that cannot be replicated on Earth."

The research also offers new insights for ground-based regenerative medicine. The team found that space-grown stem cells have unique advantages in proliferation capacity and differentiation potential—properties that may be applied to improve ground-based stem cell therapies, such as the treatment of muscular dystrophy and neurodegenerative diseases.

Linkage of the Space-Ground Collaborative Cold Chain Technology Network

From space to Earth, the full-process quality control of samples tests the collaborative capabilities of cross-disciplinary teams. The entire process is closely linked to ensure the integrity of the precious stem cell samples.

In November 2024, when the Tianzhou-8 cargo spaceship delivered the initial stem cell samples to the space station, the samples were maintained in an active state via a dedicated life support device, completing the transfer from the ground laboratory to the space station within 24 hours. During the in-orbit period, experimental data was transmitted back to the ground in real time for dynamic comparison with ground control groups.

The return phase was a model of precise collaboration. Within 1 hour after the spaceship landed on April 30, the samples were transferred to a deep-cryogenic cold chain transport box equipped with GPS positioning and real-time temperature control. 

To ensure sample safety, 95kpa Bags were specially installed inside the box. This flexible secondary packaging has passed a 95 kilopascal pressure test, providing reliable protection within a temperature range of -40℃ to +55℃. Fully compliant with UN3373 biological material transportation standards, it effectively prevents sample leakage and contamination.

A temperature accuracy of -80℃ ± 2℃ was maintained throughout the process, and transport data was recorded on-chain in real time to ensure traceability. At around 21:00 on April 30, the samples were safely delivered to the CAS Center for Space Science and Applied Research. Researchers immediately conducted status checks and verification of the returned life science experimental samples before initiating follow-up studies.

This full-chain technical system of "space culture - in-orbit preservation - ground recovery" has resulted in 6 core patents, among which the space cryoprotectant formula and space-ground cold chain connection standards have been incorporated into international guidelines for space biological sample management.

Follow-Up Research and Future Impact of Space-Bred Stem Cells

Currently, the research team is conducting thawing, recovery, and multi-omics analysis of the returned stem cells, as well as single-cell sequencing to analyze the impact of the space environment on cell epigenetics. Preliminary results show significant changes in the expression of certain aging-related genes.

Researcher Lei Xiaohua explained, "Next, we will focus on studying the 3D growth laws and developmental potential of human pluripotent stem cells in the space microgravity environment, and explore the molecular regulatory mechanisms underlying enhanced stemness. These stem cells returned from space are revealing the mysteries of how life adapts to extreme environments—and these mysteries will ultimately be transformed into forces that improve human health."

This breakthrough will not only support the construction of medical security systems for China's deep-space missions such as manned lunar landing and Mars exploration, providing key technical support for astronaut health protection during long-duration space exploration, but also is expected to drive technological innovation in the field of regenerative medicine. In the future, the research results of space-bred stem cells may be applied to the treatment of major diseases on Earth, allowing the achievements of space exploration to truly benefit human health on our planet.

As China's space station construction continues to improve, more space life science experiments will be carried out sequentially, promising more breakthroughs in space medicine, regenerative medicine, and other fields, and making greater contributions to the development of human health and aerospace undertakings.