Cryoprecipitates In Serum
The method used to thaw serum is crucial to its optimum performance. The key to proper thawing is periodic agitation. If a bottle of serum is not periodically shaken or swirled as it thaws, salt and protein gradients will form throughout the liquid portion. Within these gradients are high concentrations of salts, proteins and lipids which can lead to the formation of crystalline or flocculent precipitates.
These "cryoprecipitates" are not toxic to cell cultures, but they affect the appearance and consistency of each bottle of serum. Small amounts of cryoprecipitates are not uncommon, even in serum that is thawed using the recommended procedure. This is normal and will not affect product performance.
If serum is thawed incorrectly, a much greater amount of cryoprecipitate will form and is often insoluble. Filtering serum to remove cryoprecipitates is not recommended and could result in the loss of nutrients, such as growth factors, mitogens and other proteins.