Biological matter must be stored at the correct temperature in order to survive and thrive. Being stored at very low temperatures significantly reduces (or even stops) the usual chemical reactions that occur inside living cells. While this doesn’t sound optimal at first, freezing samples can preserve the biological matter for long periods of time.
The process of freezing cells and tissues is called cryopreservation. Biomedical scientists store their samples in cryogenic freezers to delay the growing process and maintain cell and tissue integrity for months.
You might wonder why scientists specifically use cryopreservation when working with biological samples instead of generic freezers. Let’s discuss what cryogenic freezers are and why they are used in biology labs to preserve cell and tissue samples.
What is a Cryogenic Freezer?
Unlike a generic freezer that uses an air cooler, cryogenic freezers use liquid nitrogen to freeze samples. They operate at temperatures at or below -150 degrees Celsius.
Some cryogenic freezers can use liquid carbon dioxide. Depending on the specific application and sample type, a liquid carbon dioxide cryogenic freezer might be more suitable than a liquid nitrogen option.
Why Are Generic Freezers Unsuitable for Biological Samples?
When biological samples are placed in a freezer, there is always the risk of damage to the cells and tissues. When placed in a low temperature environment using a standard freezer, biological matter is prone to ice formation.
The formation of ice crystals can damage the integrity of the sample and may lead to osmotic shock or membrane damage. Damage to your sample can disrupt and delay your experiment, forcing you to start over again.
If you only have a small amount of material to work with, it’s vital that you don’t damage it through the freezing process. Otherwise, you may not be able to get another identical sample.
What Makes Cryogenic Freezers Better Than Generic Freezers for Biological Samples?
Using a cryogenic freezer can prevent the formation of ice crystals in biological matter, reducing the risk of damage to the samples. Whole tissues or individual cell cultures can be safely stored in cryogenic conditions.
Cryogenic freezers are compact but enable a large volume of samples to be stored at once. They’re also energy-efficient so can help to protect the environment more than standard freezers.
Cryopreservation is an effective way for biology lab staff to work with cell and tissue samples for long periods of time while maintaining their integrity and quality. They can apply cryoprotective agents to samples to help with the physical and chemical freezing process. These agents further protect the samples and reduce ice crystal formation, osmotic shock, and membrane damage.
Using cryogenic freezers improves the water to ice phase transition and reduces dramatic changes in both the intercellular and extracellular environment. There is a lot of research out there that shows the benefits of cryopreservation for cell survival during the cooling and freezing processes.