Animal serum identification method and animal serum preservation method

 The medium is required for use in the cell culture process. Some media require synthetic media and animal serum. Some cells can divide normally only with the addition of serum. Therefore, animal serum is also a product frequently used by researchers. However, we still know very little about how animal sera are identified, preserved and used. How should it be identified?

Animal serum identification method:

Pale yellow transparent liquid of blood coagulation precipitation. If blood is taken out from blood vessel, put into test tube, without anti-coagulants, blood coagulation reaction will be activated, and blood will solidify rapidly, form jelly. The light yellow transparent liquid that precipitates around is serum, which can also be obtained by centrifugation after coagulation. During coagulation, fibrinogen is converted into fibrin clots, so there is no fibrinogen in serum, unlike plasma.

In blood coagulation reaction, many materials are released, and each blood coagulation factor has all changed. These components all remain in the serum and continue to change. For example, prothrombin becomes thrombin, which gradually decreases or even disappears with the storage time of serum. These are also not the same as blood plasma. Yet the material of not participating in a large number blood coagulation reaction is substantially identical with blood plasma. In order to avoid the interference of anticoagulants, the analysis of many chemical compositions in blood is all taking serum as sample.

Methods of preserving animal serum:

Serum for long-term storage should be stored at -20°C. ℃-70℃ in a low-temperature refrigerator ℃ Do not store in the refrigerator for more than one month. Because the volume of serum will increase by about 10% when it freezes, a certain volume of space should be reserved before being frozen into a low-temperature refrigerator, otherwise it will be easily contaminated or the glass bottle will freeze and crack.

2. The serum provided by the general manufacturer is sterile and does not need to be sterilized by filtration. If you find that the serum has suspended matter, you can add serum to the culture medium and filter it together, do not filter the serum directly.

Serum thawing: thawing of bottled serum requires a step-by-step thawing method: -20°C to -70°C, put the serum in a low-temperature refrigerator and thaw in the refrigerator for one day at 4°C. Then move it to room temperature, dissolve it completely and repack it. During the dissolution process, it needs to be shaken evenly (be careful not to cause air bubbles) to make the temperature and ingredients uniform and reduce precipitation. Do not directly thaw the serum from -20°C to 37°C, as this may easily lead to protein aggregation and precipitation due to excessive temperature changes.

Heat inactivation refers to heating the completely thawed serum at 56°C for 30 minutes. During the heating process, the rules must be shaken evenly. The purpose of this heat treatment is to inactivate the complement in the serum. Heat treatment is generally not recommended as it can lead to a significant increase in serum sedimentation.