The term “biological storage” covers quite a wide range of options as the conditions required tend to vary according to the precise nature of the material to be stored. In essence, the term implies storing such materials under the conditions that are necessary for them to retain their prior activities or integrity until they are returned to the environment from which they were removed.

A simple example might be immersing a partially dissected laboratory animal, such as frog or rat, in a jar or tank filled with formaldehyde in order that a student can continue the dissection at some later stage. In such cases, there is no other requirement than to prevent putrefaction and so this rather basic precaution should prove more than adequate. However, in the case of genomic or plasmid DNA samples or a growing culture of eukaryotic cells, the requirements will be far more stringent for both and will also differ in each case. In the case of bacterial cultures, the biological storage requirements will vary, depending upon whether it is required to permit further growth or to inhibit it.

Today, advances in almost all branches of medicine and research, including some that never even existed just a few decades ago, have led to an increased demand for such facilities. For instance, bone marrow is now routinely transplanted into patients with leukaemia and other systemic malignancies while stem cell research promises a new approach to medicine in which stem cell injections could see damaged vital organs reliably repaired or even whole organs cloned to provide a perfect replacement.

To these must be added the successes in artificial insemination, in-vitro fertilisation, and the other techniques now employed in assisted reproduction. All of these, however, would simply not be possible without suitable systems for the safe storage of biological materials such as the active ova and spermatozoa required to help childless couples.

In almost all cases, refrigeration forms the basis of these preservative measures, with some materials requiring no more than the 4 oC level obtainable with a domestic refrigerator, whilst others may need to be cooled to -20 oC or even as low as -80 oC. To achieve these ultra-low temperatures, liquid nitrogen is usually the material of choice. However, its use requires stringent safety measures at every stage. These include the storage and handling of the liquefied gas as well as the freezing, storing, transportation, and thawing of specimens. With the aid of suitable equipment, however, each of these processes is both simplified and made safe.

Among the requirements that are crucial for safe and reliable biological storage are liquid nitrogen vapour storage freezers; insulated Dewar flasks with which to store and dispense the liquefied gas; shippers that allow the critical temperatures to be maintained during transportation; and vials and straws to hold the specimens. Equally important are alarms to warn of low liquid levels and to monitor oxygen concentration as well as protective gloves and aprons for the handlers.

IEPSA is South Africa’s leading supplier of these items, serving hospitals, universities and research laboratories for almost four decades. To guarantee both quality products and service excellence, all equipment for these purposes is sourced from leading industry internationals, Chart and Cryo Bio System.

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