Liquid nitrogen, which is more expensive than dry ice, is generally used for biological sample conservation and there are more potential risks with respect to its handling. However, for different types of samples to be stored in the glass phase (in this case it is referred to temperatures below -150 °C), nitrogen in its liquid phase is the only option, since it has a boiling point of -195,8 °C and a freezing point of -210 °C. This cryogenic preservation process can be useful for:
- Stem cells
- Bone marrow
- Cord blood
- Blood components
- Parts of organs and cultures of tissues, skin, among others
- Reproductive material such as oocytes (eggs) and sperm
- Plant cells
- Fragments of bone, cartilage, among others
What are the aspects to consider when working with liquid nitrogen?
The use of liquid nitrogen for the storage of biological samples should be done with caution. This popular coolant boils quickly when it touches surfaces that are hotter (or less cold), which decreases the efficiency of the procedure. Additionally, when a substance boils at temperatures below the freezing point of water, an effect occurs where an insulating cover of nitrogen bubbles forms on the cooled object, known as the Leidenfrost effect.
This effect can be partially compensated by immersing objects in a mixture of solid and liquid nitrogen, rather than just the element in its liquid form, thus achieving faster cooling. It should not be neglected, that people who handle liquid nitrogen should do with all precautions and safety standards to avoid any accident.
What kind of containers are required to work at low temperatures?
Special tanks and containers compatible with cryogenics are needed to work at extremely low temperatures. In general, these vessels have a vacuum chamber and payload depending on the use, but in general, these two cases may occur:
- A relatively small container, sometimes only a few cubic centimeters, where the sample is placed in special sample holders for cryogenics.
- A container of relatively large volume, where liquid nitrogen is transported and stored.
Why is it necessary to keep biological samples in cryogenics?
Liquid nitrogen has the ability to maintain extremely cold temperatures. In these cryogenic conditions, the presence of impurities is limited and the processing of substances with a high reactivity is facilitated. This is because extreme cold improves the selectivity of the reaction, and secondary reactions that generate variations in the initial composition of the sample are avoided or reduced.
An important aspect of cryogenic cooling is that the formation of ice crystals is avoided. Under these conditions, cells and tissues are preserved in a state called vitrified. In this condition, the water present in the sample passes directly into the amorphous ice phase, allowing the sample to be frozen in the long term. Such cooling conditions are appropriate in the following areas:
- The storage of cells in the laboratory work
- Cryopreservation of blood, germ cells and other biological materials and samples
- Preservation of Tissues from Surgical Organ Removal for Further Medical Studies
- Cryoconservation of genetic resources of animal species. Their storage is done not only for research and development purposes, but the cryoconserved specimens can revive endangered or extinct species
- Synthesis reactions to ultra-low and boiling temperatures under controlled conditions, which are typical of advanced processes
- Cooling baths and vacuum pump traps used in chemical research
Why Choose Kalstein Nitrogen Tanks?
Nitrogen tanks from the laboratory equipment and instrument manufacturer Kalstein, are specially designed vessels to store nitrogen for researchers who require to store biological samples in cryogenics. By design (vacuum insulation between internal cavities) and the type of material (aluminum) from which they are built, they are resistant, durable and good thermal insulators. Incorporate liquid nitrogen absorbers (LN2) that prevent it from spilling by accident, in addition they are retained by a stainless-steel mesh so that the sample does not become contaminated. For other technical specifications, purchase or price consultation, you can check the link HERE, or on the main page HERE, where you can learn about other instruments for medical research that may be of interest to you.