Cryopreservation, the process of preserving biological tissues by cooling them to subzero temperatures, might sound like something out of science fiction. However, scientists have been developing this technology for nearly a century.

For most of that time, progress was limited—until 2023, when researchers at the University of Minnesota successfully transplanted a cryopreserved kidney into another rat. This achievement demonstrated the potential for using cryopreserved organs in future human transplants.

Preventing cracking in frozen organs
Cryopreserving larger organs poses a significant obstacle because the tissues are prone to cracking during rapid cooling. Avoiding these fractures is critical for maintaining organ integrity in human preservation and transplantation. A research team from the J. Mike Walker ’66 Department of Mechanical Engineering at Texas A&M University, led by Dr. Matthew Powell-Palm, has published a paper detailing a new cryopreservation technique that may prevent cracking in organs.

To preserve organs outside the body for longer periods, scientists use a process called vitrification. This method freezes tissue in a specialized solution, keeping it in a glass-like state that prevents damage from ice crystal formation. By modifying the composition of the vitrification solution, researchers can analyze how different properties influence the likelihood of cracking in an organ.

“In this study, we investigated different glass transition temperatures, which we believe play a dominant role in cracking,” said Powell-Palm, an assistant professor of mechanical engineering. “We learned that higher glass transition temperatures reduce the likelihood of cracking.”

Designing better biocompatible cryosolutions
Equipped with the knowledge that higher transition temperatures are less likely to cause cracks than lower temperatures, researchers can focus on creating aqueous vitrification solutions with higher glass transition temperatures to help avoid cracking.

“Cracking is only one part of the problem,” Powell-Palm said. “The solutions need to be biocompatible with the tissue as well.”