Scientists develop new approach to ice-free cryopreservation

Scientists have developed a new approach to ice-free cryopreservation that could allow a much wider use of extreme cold for tissue preservation and even whole organs for later use, PTI reported.

"This could be an important step toward the preservation of more complex tissues and structures," said Adam Higgins, an associate professor in the Oregon State University School of Chemical, Biological and Environmental Engineering in US.

Cryopreservation had already found widespread use preserving semen, blood, embryos, plant seeds and a number of other biological applications.

It was, however, often constrained by the crystallisation that occurred when water froze, which could damage or destroy tissues and cells, Higgins said.

This was much like food products losing much of their texture when thawed, after being stored in a freezer.

To address this, researchers had used cryoprotectants of different types that could help reduce cell damage during the freezing process - among them was ethylene glycol, the compound often used in automobile radiators for prevention of freezing.

According to Higgins, due to the toxicity of many cryoprotectants, they could damage or kill the very cells they were trying to protect from the forces of extreme cold.

Scientists had developed a mathematical model for stimulating the freezing process in the presence of cryoprotectants, and identified a way to minimise damage.

They found that if cells were initially exposed to a low concentration of cryoprotectant and time was allowed for the cells to swell, then the sample could be vitrified (ice-free cryopreservation) after rapid addition of a concentration of cryoprotectants. According to Higgins, the end result was much less overall toxicity.