The development of serum cell culture, the quality of the medium is the key, and the main components of the medium of animal serum for cell growth and reproduction play an important and even irreplaceable role. In the application of animal serum, bovine serum is the most widely used, so serum is one of the important raw materials in pharmaceutical biotechnology products. To ensure the quality of serum is also an important part of the promotion of the quality of biological products. 1. serum type
Currently used in tissue culture serum is mainly bovine serum, culture of some special cells also use human serum, horse serum, etc.. The reasons for choosing to use bovine serum for cell culture are: sufficient sources, mature preparation techniques, and a deeper understanding of the serum after a long period of application. Bovine serum is suitable for the majority of mammalian cells, but this does not preclude the use of other animal serums in the culture of certain cells.
Bovine serum is the most abundant natural medium used in cell culture, rich in nutrients essential for cell growth, and has extremely important functions. Bovine serum is divided into calf serum, neonatal serum and fetal bovine serum. Fetal calf serum should be obtained from cesarean sectioned fetal cows; neonatal calf serum should be obtained from newborn cows within 24 hours of birth; calf serum should be obtained from calves between 10-30 days of birth. Obviously, fetal calf serum is the highest quality, because the fetal cattle have not been exposed to the outside world, the serum contains the least antibodies, complement and other harmful components to the cells. 2. The main components of serum
Serum is a very complex mixture of plasma to remove the fibrous proteins and the formation of a very complex mixture of its constituents, although most of the components are known, but there are still part of the still not clear, and the composition of the serum and the content of the blood supply animals with sex, age, physiological conditions, and nutritional conditions. The composition and content of serum often vary according to the sex, age, physiological and nutritional conditions of the blood donor. Serum contains a variety of plasma proteins, peptides, fats, carbohydrates, growth factors, hormones, inorganic substances, etc., which are physiologically balanced to promote cell growth or inhibit growth activity. The research on the composition and role of serum has made great progress, but there are still some problems. Firstly, there may be hundreds of serum components, but the exact composition and content of serum and its mechanism of action are still unclear, especially some of the peptide growth factors, hormones and lipids have not been fully recognized, which has brought many difficulties to the research work. Secondly, serums are produced in batches, and there are great differences between batches, and serums are preserved for up to one year, therefore, it is extremely difficult to ensure the similarity of each batch of serums, which limits the standardization and continuity of experiments. Thirdly, it cannot be ruled out that serum contains perishable substances, which is considered to be one of the reasons for "deterioration in the bottle".3. The main role of serum
Provides basic nutrients: amino acids, vitamins, inorganic substances, lipids, nucleic acid derivatives, etc., which are necessary for cell growth.
Provide hormones and various growth factors: insulin, adrenocorticotropic hormone (hydrocortisone, dexamethasone), steroid hormones (estradiol, testosterone, progesterone), etc.. Growth factors such as fibroblast growth factor, epidermal growth factor, platelet growth factor, etc. .
Providing binding proteins: Binding proteins carry important low-molecular-weight substances, such as albumin, which carries vitamins, fats, and hormones, and transferrin, which carries iron. Binding proteins play an important role in cellular metabolism.
Provides pro-contact and stretch factors to protect the cell wall from mechanical damage.
Certain protective effects on cells in culture: some cells, such as endothelial cells and myeloid cells, can release proteases, which are neutralized by the presence of anti-protease components in serum. This effect was discovered accidentally, and now serum is used purposefully to terminate the digestive action of trypsin. Trypsin has been widely used for the digestion of walled cells. Serum proteins form the viscosity of the serum, which protects the cells from mechanical damage, especially during agitation of suspension cultures, where viscosity plays an important role. Serum also contains some trace elements and ions, they play an important role in metabolic detoxification, such as SeO3,
Selenium, etc. 4. Disadvantages of using serum in cell culture
Serum has a complex composition, although it contains many components that are beneficial to the cells, it also contains components that are detrimental to the cells, so serum has a few obvious shortcomings:
For most of the cells, in the in vivo state, serum is not their contact physiology. Serum is not a physiologic fluid that they come into contact with, but only in the healing of injury