jäädytysprosessi

Jäädytysprosessi is a Finnish term that translates to "freezing process" or "cryopreservation" in English. It refers to the method of preserving biological material, such as cells, tissues, or even whole organisms, by cooling them to very low temperatures, typically below -130 degrees Celsius. At these temperatures, metabolic activity effectively stops, preventing degradation and maintaining the viability of the preserved material for extended periods.

The process usually involves a cryoprotective agent (CPA), a substance that protects the biological material from damage caused by ice crystal formation during freezing. Common CPAs include glycerol and dimethyl sulfoxide (DMSO). These agents infiltrate the cells and reduce the formation of large, damaging ice crystals by increasing the solute concentration of the intracellular water, thus lowering its freezing point.

The cooling rate is a critical factor in successful cryopreservation. Rapid cooling can lead to thermal shock and the formation of intracellular ice, which can be lethal to cells. Conversely, cooling too slowly can result in the formation of large extracellular ice crystals, which can dehydrate cells and cause damage. Therefore, a carefully controlled cooling rate, often achieved using programmable freezers, is essential.

Upon thawing, the biological material needs to be warmed rapidly to prevent ice crystal growth during the warming phase. The CPA is then removed to avoid toxicity. Jäädytysprosessi has numerous applications in various fields, including fertility preservation (sperm, eggs, embryos), cell line preservation for research, and conservation of endangered species.