Since the dawn of time, we humans have been searching for a way to prolong our lifespan. With the advancements in medicine, we managed to averagely live up to about a hundred years. But there is also a way to extend that time by preserving our bodies in freezing temperatures. Unfortunately, that type of cryopreservation is not what this post is about. Maybe some other time.
Picture 1: A snowflake
The cryopreservation we are talking about is the preservation of different samples, may they be cells or whole tissue, plants or animals. The gist is freezing and storing samples at a very low temperature (-90°C and lower) in liquid nitrogen. This enables the biological material to stay dormant for a longer period of time because the metabolic activity inside the cells slows down or stops completely.
Picture 2: Cells with nuclei
From a practical standpoint this method is very useful in a wide range of scientific fields where our company, Pharsol, is actively present.. The use of cryopreservation can be categorised accordingly:
- cryopreservation of cells or organs
- cryosurgery
- biochemistry and molecular biology
- food sciences
- ecology and plant physiology
- many medical applications (i.e. blood transfusion, bone marrow transplantation, artificial insemination, in vitro fertilization (IVF)
Picture 3: Portrayal of a soon-to-be family
An important part of cryopreservation is also the use of substances called cryoprotectants or CPAs (cryoprotective agents). Their purpose is to prevent cryoinjury a.k.a. “causing damage to the biologic material” being frozen. This occurs mainly because of the phase changes the intra- and extracellular water undergoes once it starts to freeze. The CPAs help prevent that.
There are also different types of desired preservation. Different tissues have different “preferences” when it comes to staying viable for further use after preservation and, naturally, we apply different methods to different biologic samples. So how is it done? By one of the following ways:
- slow freezing
- vitrification
- subzero nonfreezing storage
- preservation in the dry state
Pictures 4, 5: Liquid nitrogen tank (left); Blood sample, about to be frozen (right)
Once the samples are frozen they are “stuck in time” until they get warmer again. Another problem here is the moving of samples from one stand to the other or general manipulation of the vials. To solve this problem check out the CryoHolder.
Sources:
Theodora K. Nannou et. al. (2016). Cryopreservation: Methods, Equipment and Critical Concerns. International IIR Conference of Cryogenics and Refrigeration Technology, Bucharest
