How did the researchers do it?

The team did not use the full CAHS protein. Instead, they identified a smaller section of it that still provided the protective effect they needed—a simplification that makes the strategy more practical.

Their workflow looked like this:

• Combine the CAHS protein fragment with trehalose at a low temperature.
• Freeze the treated mouse red blood cells in liquid nitrogen.
• Thaw the cells and wash the CAHS-trehalose mixture away using centrifugation, a standard laboratory spinning technique that separates components by weight.

The two components changed how ice formed and melted inside the samples, shielding the cells from the crystal damage that normally destroys frozen tissue. The washing step proved straightforward, without the harsh processing that glycerol removal demands.

The results: up to 89% of mouse red blood cells preserved with the new method recovered fully, versus about 82% of cells frozen with glycerol.

Did the preserved blood actually work in living animals?

Frozen, thawed and washed cells are only useful if they behave normally inside a body. To check this, the researchers transfused the cryopreserved blood into anemic mice—animals with abnormally low red blood cell counts.

The transfusion significantly improved the mice's red blood cell counts and hemoglobin levels, the protein that carries oxygen through the bloodstream. Just as important, the procedure triggered no inflammatory response, an early sign that the treated cells are biocompatible.

What are the limitations?

The findings are preliminary in several ways that readers should weigh carefully.

The experiments involved mouse blood, not human blood, and the study is an early proof of concept rather than a tested clinical protocol. A seven-percentage-point improvement in cell recovery sounds promising, but researchers have not yet shown the method works at the scale, safety standards and regulatory requirements of human blood banking. The authors themselves frame the work as a first attempt that would need considerable further development before reaching patients.

The study also leaves open questions the team hopes to pursue, including whether the same approach can protect other types of cells and tissues during freezing.

What comes next?

The researchers see two longer-term directions. First, they hope the work guides the design of better cryopreservation strategies generally—not just for blood. Second, and more ambitiously, they suggest the tardigrade-inspired approach could lead to protective strategies for blood that function at room temperature, eliminating freezing altogether.

For now, the takeaway is modest but real: a protein fragment borrowed from an animal that survives the vacuum of space has kept mouse blood cells alive through liquid-nitrogen freezing at rates that beat the current standard. Whether that success travels from mice to humans is the question the field will now work to answer.

The paper, by Tianwen Xi and colleagues, appears in ACS Applied Materials & Interfaces (2026), DOI: 10.1021/acsami.6c12445.