As researchers have slowly gained greater insight into the structure and function of living cells, the need to develop methods for the safe and reliable storage of biological materials has been growing in parallel. To be of value, the methods employed must, of course, preserve the physical integrity of the stored material. However, where that material happens to be cellular and alive, it is often crucial to ensure that it also remains viable.

The materials to be stored vary widely. In some cases, the requirement may be limited to the relatively short-term preservation of bodily fluids, such as whole blood, plasma, urine, and cerebrospinal fluid prior to routine chemical or microbiological testing. For such purposes, the sub-ambient temperature provided by a domestic refrigerator should generally be quite sufficient to maintain such specimens for the time required.

The requirements for biological storage have become more stringent with the emergence of new fields such as organ transplantation, assisted reproduction, DNA sequencing, and genetic engineering. In these fields, the requirement is frequently for samples to be preserved for periods far longer than those necessary in a routine pathology laboratory. Although the optimal temperature for the prolonged maintenance of genomic and plasmid DNA is -20° Celsius or less, to preserve sampled cells from a cheek swab for DNA studies, for example, requires a temperature of -80° Celsius or less. In the case of eukaryotic cells in storage media, immersion in liquid nitrogen is necessary.

Given the vulnerability of most biological materials, ensuring optimal storage conditions can be crucial. It is, therefore, important for those who handle them to be aware of the optimal conditions that apply to each type of material they are required to deal with based on the period of time for which it may be necessary to preserve them. Just as important as this type of background knowledge, of course, will be the nature of the equipment that is to be employed for this purpose. Where the extremely low temperatures associated with cryopreservation may be necessary, the safety of those who handle the samples will be just as important as that of the samples themselves.

The storage requirements for biological materials in use today are aimed at minimising physico-chemical changes, and have been determined through experiment. Armed with this knowledge, companies have lost no time in developing the various items of equipment necessary to maintain those conditions, as well as for the collection and safe handling of the many different types of material that their clients may need to be preserved. One such company and a world leader in the field of cryopreservation is Planer PLC.

The UK-based manufacturer offers a product range that includes controlled rate freezers together with management software, liquid nitrogen storage vessels, and a full complement of cryogenic accessories. To ensure the safety and continued integrity of biological materials during storage, Planer PLC also offers a range of monitoring and alarm systems.

Monitoring systems and other equipment for use in IVF procedures, bone marrow transplantation, aquaculture, and numerous other applications are available in South Africa from IEPSA.

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