Cryogenics are an old science fiction dream, but today we still struggle to store large tissues without harming them. Now a breakthrough could lead to a safer, more reliable approach.
"This could be an important step toward the preservation of more complex tissues and structures"
Overcoming past challenges
Cryopreservation of biological material is commonplace, but there are remaining challenges. The initial problem with freezing any cell is crystallization, in which ice crystals form and rupture cells. This was overcome by using molecules like ethylene glycol, which essentially act like anti-freeze and prevent crystallization from happening. These are very effective, but they're also often toxic; damaging or killing some cells in the process. This has made storage of larger tissues very challenging.
Hope for the future
In new research, a mathematical model was used to simulate this freezing process in the company of common cryoprotectants. By studying the process and its effect on the cell more closely, the team was able to work out a new strategy that results in far less damage. They discovered that initially exposing cells to a low concentration of these molecules until they have had time to swell, a second large concentration of cryoprotectant can quickly freeze them with less collateral. Cell survival in most storage methods is around 10%, but this method increased survival up to 80%.
"The biggest single problem and limiting factor in vitrification is cryoprotectant toxicity, and this helps to address that. The model should also help us identify less toxic cryoprotectants, and ultimately open the door to vitrification of more complex tissues and perhaps complete organs."
Progress in this field could help many other areas too, such as long term organ storage to create a better 'library' to match patients and storing human tissue engineered in the lab for personalised drug testing. It may even lead the way to optimised cryogenic storage of patients with severe injury or incurable disease.
Read more at MedicalXpress