Biological applications of sample/95kPa bags

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1. Storage of biological samples
2. -196℃, -150℃ cryogenic freezing

Liquid nitrogen (-196°C) is recognized as the most reliable method of sample preservation. However, because the sample cannot be completely immersed in liquid nitrogen, free fragments may bring potential risks of cross-contamination, so the gas phase liquid nitrogen (-150°C) was developed. The best preservation method is to place the sample above liquid nitrogen and surrounded by gas phase liquid nitrogen, which can well prevent the risk of cross-contamination. It can also be refrigerated by an electric refrigerator to reach a low temperature of -150°C, thus meeting the long-term storage needs of samples. Since -137°C is the glass transition temperature of water, below this temperature all biochemical reactions in cells that can cause content degradation are inactive, thus meeting long-term storage requirements.

2. -80℃

-80°C cryopreservation is a method of preserving frozen nucleic acid samples: in biological sample banks that do not have liquid nitrogen storage conditions, you can also consider using -80°C deep-freezing refrigerators to preserve samples. Studies have shown that at -80°C, DNA production value, integrity and RNA production value can be maintained for up to 7 years without significant changes, and RNA integrity decreases after 5 years of cryopreservation. Therefore, it is recommended to aliquot at the appropriate time of storage, add RNA-specific stabilizer and then freeze at -80°C, which is more conducive to the preservation of RNA.

Regarding the preservation of proteins, deep cryogenic freezing is now the main method, which can well maintain its stability. Short-term storage can also be kept in a low-temperature refrigerator at -20°C.

2. Sample transportation conditions
3. Whole blood/plasma/serum/dried blood tablets

DNA: It can be transported to the laboratory at room temperature within 24 hours, transported to the laboratory within 72 hours and placed at 2-8°C, and transportation of 72 hours and longer needs to be carried out at -20°C.

RNA: Separate plasma within 4 hours, and can be transported to the laboratory within 5 days and stored at 2-8°C. When transported for 5 days or longer, it must be kept at -20°C.

Dried blood tablets can be shipped at room temperature.

2. Alveolar lavage fluid

It can be transported to the laboratory at room temperature within 24 hours, and must be refrigerated at 2-8°C within 72 hours. For shipments of 72 hours and longer, -70°C or more stringent conditions must be used.

3. Bone marrow

Bone marrow specimens should be transported at 2-8°C, and if used for RNA analysis, RNA stabilizers should be added.

4. Cheek cells

Nucleic acids can be stable for 1 week at room temperature and can be transported at room temperature. To detect RNA, they need to be placed in an RNA stabilizer.

5. Lymphocytes

Lymphocytes isolated from blood need to be refrigerated and transported at 2-8°C. If they cannot be extracted in time, they should be stored below -70°C.

6. Cerebrospinal fluid

DNA virus detection: needs to be transported at 2-8 degrees Celsius and should be stored at -20 degrees Celsius or -70 degrees Celsius or lower.

RNA: Immediately cool down on ice and transport to the laboratory on dry ice.

7. Extract

DNA virus detection: needs to be transported at 2-8℃ and should be stored at -20℃ or -70℃ or lower.

RNA: Immediately place on ice to cool down or place in RNA stabilizer for transportation.

8.Organization

DNA: Fresh tissue should be placed immediately at -20°C and kept on ice for storage.

RNA: Fresh tissue is quickly frozen in liquid nitrogen immediately after collection for transportation and storage.

Paraffin embedding can be transported and stored at room temperature.

9. Sputum

It can be transported to the laboratory at room temperature within 30 minutes, otherwise it should be transported at 4-8°C.

10.Feces

It can be collected with the help of stool collection box and stool collection tube, and a sample the size of a soybean grain is enough. Carry out nucleic acid extraction or cryopreservation at -80°C within 4 hours.

11. Cervical and urethral swabs

Ship in the shipping medium recommended by the test reagent manufacturer.

12. Plant samples

Collect fresh samples with normal body shape and put them into sample bags and mark them; if there is soil in the samples, they generally need to be washed, then dried and nucleic acid extracted as soon as possible; transported and stored at room temperature or -20°C.

It should be noted here that samples should be stored under stable conditions and repeated freezing and thawing should be avoided.