Samples are stored in various controlled environments to preserve their integrity and prevent degradation. The specific storage method depends on the type of sample and the intended use.
Here's a breakdown of common storage methods:
-
Refrigeration: Storing samples in refrigerators (typically around 4°C) is common for short-term preservation. This slows down enzymatic activity and microbial growth.
-
Freezing: Freezing samples, often at -20°C, provides longer-term storage by further reducing enzymatic activity.
-
Ultralow Temperature Freezing: For long-term preservation of sensitive biological samples like proteins and mRNA, ultralow temperature freezers (-80°C) are used. These freezers significantly slow down degradation processes.
-
Cryogenic Freezing: Cryogenic freezers, which can reach temperatures as low as -150°C, are used for extremely long-term storage. Some samples are even stored in liquid nitrogen at -196°C. This method essentially halts biological activity.
-
Specific Containers: Samples are typically stored in specialized containers, such as cryovials or microcentrifuge tubes, designed to withstand extreme temperatures and prevent contamination.
-
Desiccation: For certain materials, like seeds or some biological tissues, drying (desiccation) is used to remove water, which inhibits microbial growth and enzymatic reactions.
Here's a table summarizing common storage methods and their applications:
| Storage Method | Temperature | Common Applications |
|---|---|---|
| Refrigeration | ~4°C | Short-term storage of reagents, cultures, and samples. |
| Freezing | -20°C | Medium-term storage of DNA, proteins, and other biomolecules. |
| Ultralow Temperature Freezing | -80°C | Long-term storage of sensitive biological samples like RNA. |
| Cryogenic Freezing | -150°C to -196°C | Very long-term storage of cells, tissues, and organisms. |
| Desiccation | Room Temperature (Dry) | Storage of seeds, dried specimens, and some chemicals. |
The selection of an appropriate storage method is critical to ensure that samples remain viable and useful for future analysis or experimentation.
