Question 4: What should be done if flocculent substances are found after serum thawing?
There are many reasons for the appearance of flocculent substances in serum, and the most common reason is due to the denaturation of lipoproteins in serum; Fibrin (one of the coagulation proteins) also exists in serum after thawing, and is one of the main causes of flocculent substances. The production of these flocculent substances will not affect the quality of the serum itself. If you want to remove these flocculent precipitates, you can divide the serum into sterile centrifuge tubes, centrifuge briefly at 400g centrifugal force, and then add the supernatant after centrifugation to the culture medium for filtration. We do not recommend filtering the serum directly to remove these flocs as it may clog the filtration membrane.
Question 5: Why does fetal bovine serum stored in the refrigerator precipitate?
When stored at 2-8 ℃, various proteins and lipoproteins in fetal bovine serum (such as cold agglutinin, fibrinogen, hyacinin, etc.) may aggregate and form precipitates or visible turbidity. The production of these precipitates will not affect the quality of serum. It is recommended to store fetal bovine serum at -20 ℃ to avoid repeated freezing and thawing.
Question 6: How to avoid the formation of sediment?
We suggest that you pay attention to the following operations when using serum: ① When thawing serum, please follow the recommended step-by-step thawing method (-20 ℃ to 4 ℃ to room temperature)
The change is too large (such as -20 ℃ to 37 ℃), and experiments have shown that it is very easy to produce precipitates When thawing serum, please gently shake it evenly at any time to ensure uniform temperature and composition, and reduce the occurrence of precipitation Do not keep the serum at 37 ℃ for too long. If left at 37 ℃ for too long, the serum will become turbid Unstable components can also be damaged as a result, affecting the quality of serum The thermal inactivation of serum can easily cause an increase in sediment, and this step may not be necessary unless necessary If serum heat inactivation is necessary, please follow the principle of 56 ℃ for 30 minutes and shake evenly at all times. Excessive temperature, prolonged exposure, or uneven shaking can all lead to an increase in sediment.
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