What is “cryopreservation” and how to improve it?
Cryopreservation basics and tips for using it.
Since the dawn of time, we humans have been searching for a way to prolong our lifespan. With the advancements in medicine, we manage to 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.
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. The metabolic activity inside the cells slows down or stops completely because of the low temperatures.
Practical use of cryopreservation
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
- 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)
Cryoprotectants – the defending agents
An important part of cryopreservation is 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” during the freezing. This occurs mainly because of the phase changes that 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
- subzero nonfreezing storage
- preservation in the dry state
Once we freeze the samples 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.
- Theodora K. Nannou et. al. (2016). Cryopreservation: Methods, Equipment and Critical Concerns. International IIR Conference of Cryogenics and Refrigeration Technology, Bucharest
- Nagy, Zsolt Peter, Varghese, Alex C., Agarwal, Ashok (Eds.) (2017). Cryopreservation of Mammalian Gametes and Embryos
- Elliot GD, Wang S, Fuller BJ (2017). Cryoprotectants: A review of the actions and applications of cryoprotective solutes that modulate cell recovery from ultra-low temperatures.