Biological storage is the systematic process of preserving living biological materials outside of their natural environment for long periods. This practice establishes controlled environments that halt or significantly slow down natural degradation. By safeguarding these biological resources, scientists and medical professionals ensure that cells, tissues, and genetic material remain viable for future research, health applications, and conservation efforts.
Defining Biological Storage and its Core Function
Biological storage involves preserving a wide range of materials, including DNA, RNA, proteins, cells, tissues, and reproductive materials. These specimens are collected from humans, animals, and plants, forming extensive collections known as biobanks or biorepositories. The core function is to maintain the sample’s integrity and viability, ensuring it can perform its intended biological function when retrieved, such as replicating or providing genetic data.
True long-term biological storage differs significantly from simple refrigeration or commercial freezing. Standard freezing often leads to damaging ice crystals that rupture cell membranes and make the material unusable. Specialized storage requires controlled, ultra-low temperature environments, typically involving ultra-low temperature (ULT) freezers or liquid nitrogen, to minimize degradation and halt biological activity. This infrastructure must also include robust tracking systems and quality control measures to ensure each sample is properly cataloged and accessible for decades.
Key Methods for Maintaining Viability
The most common technique for long-term biological preservation is cryopreservation, which involves cooling biological material to extremely low temperatures, often between -135°C and -196°C. Liquid nitrogen, at approximately -196°C, is used because it effectively suspends all metabolic and chemical activity within the cells. At this temperature, the material enters a state of suspended animation, allowing for indefinite storage without significant degradation.
A significant challenge in cryopreservation is preventing damage from ice crystal formation, which is why cryoprotectants are introduced before cooling. These specialized substances, such as glycerol or dimethyl sulfoxide (DMSO), penetrate the cells and lower the water’s freezing point. This prevents the formation of destructive ice crystals that would otherwise cause cell death by rupturing membranes.
The cooling rate is precisely managed through controlled-rate freezing, typically aiming for a gradual rate of approximately -1°C per minute. This slow, deliberate cooling minimizes osmotic stress and water loss from the cells. Other methods, like lyophilization or freeze-drying, are used for materials that do not require viability, such as certain proteins and purified DNA, by removing the water content entirely through sublimation. Lyophilization allows for storage at ambient temperatures, simplifying transport, but is not suitable for preserving living cells for later use.
Applications in Human Health and Scientific Research
Biological storage is foundational to modern medicine and scientific discovery, providing the materials necessary for breakthroughs in human health. Biobanking, the systematic collection and storage of human biological samples, is central to this effort. These collections of blood, tissue, and DNA allow researchers to study diseases, identify biomarkers, and understand the complex mechanisms behind various human conditions.
In regenerative medicine, biological storage enables the banking of stem cells, particularly from umbilical cord blood, for future therapeutic use. These stored cells retain their potential to develop into different cell types, offering a resource for repairing damaged tissues or treating blood disorders. This provides a form of biological insurance, ensuring a patient’s own matched cells are available for emerging therapies.
The availability of large, standardized collections of patient samples is accelerating personalized medicine. Researchers use stored tumor biopsies and blood samples to trace disease progression and identify genetic factors that influence drug response. This allows clinicians to tailor drug treatments more effectively, optimizing therapies for a patient’s unique biology. Pharmaceutical companies also rely on these biobanks for drug discovery, using preserved samples to test new compounds and evaluate effectiveness.
The Role of Biological Storage in Conservation and Biodiversity
Biological storage plays an important role in safeguarding global biodiversity and ensuring agricultural security. Gene banks and seed banks are a primary example, storing genetic material from crops and wild plants to protect against threats like climate change, pests, or disease. Facilities like the Svalbard Global Seed Vault, which holds nearly a million plant seed samples, serve as ultimate backup repositories for the world’s plant genetic diversity.
These repositories provide scientists with diverse genetic resources to breed more resilient and productive agricultural systems. For seeds that cannot tolerate standard drying and freezing methods, such as those from coffee or coconut, cryotechnologies store plant tissues or embryos in liquid nitrogen. This allows for the conservation of plant species whose seeds are not equipped for conventional storage.
Similar efforts are underway for animal species through “frozen zoos,” which are cryogenic biobanks preserving living cell lines and gametes from wildlife. The San Diego Zoo Wildlife Alliance’s Frozen Zoo holds the largest collection of its kind and serves as a genetic insurance policy for endangered species. The stored genetic material offers the potential for genetic rescue through advanced reproductive technologies, ensuring that lost genetic diversity can be reintroduced into threatened populations to enhance their ability to adapt to changing environments.