Role of Serum and its Supplements

Introduction Animal Cell Culture can be described as in vitro maintenance and propagation of animal cell using a suitable nutrient media. Culturing is the process of growing animal cell artificially. The selection of the medium depends upon the type of cells to be cultured and also the purpose of culture. Purpose of Animal Cell Culture can be growth, differentiation, or even desired products like pharmaceutical compounds. Animal Cells are cultured using a completely Natural Media, or an Artificial Media (along with some natural products).

Natural Media In the in vitro cultivation of animal cell culture technique natural media are obtained from biological sources are used. For e.g. : Body Fluid such as plasma, serum, lymph, amniotic fluid and much more are used. These fluids used as animal cell culture media Tissue extract such as extract of liver, spleen, bone marrow and leucocytes are used. Commonly used is Chick embryo. Plasma clots are also used and now they are commercially produced as culture media. Bovine Embryo extract are also prepared using bovine embryos of up to 10 days age.

Artificial Media The artificial media contains partly or fully defined components. The basic criteria for choosing a artificial media for ACC is that the culture media should provide all the required nutrients to the cell. Media should maintain the physiological pH optimum for the cell type with the help of buffering system. The ACC media should be sterile and isotonic to the culturing cells. For promoting cell growth and proliferation, many types of ACC media are designed by adding varying different constituents. For e.g.. Serum containing media and serum free media.

Serum Containing Media Serum media is an example for natural media. Natural media are very useful and convenient for a wide range of ACC . But they also have got disadvantages. Major reasons for using synthetic media are for immediate survival of cells, for prolonged survival, for indefinate growth and also for specialized functions. The serum provides various plasma proteins, peptides, lipids, carbohydrates, minerals and some enzymes.

The components of the serum serve the following functions : Serum provides basic nutrient to the cell. The nutrients are present in the solution . Serum also contains hormones e.g., Insulin and growth factors e.g., platelet- derived growth factors, epidermal growth factors etc., which play a major role in stimulating cell growth and function. Serum helps in the attachment of the cell e.g., fibronectin, which promote cell to substrate interaction. Serum also acts as the spreading factors i.e., it helps the cell to spread out before they begin to divide. Serum also function as binding protein e.g., albumin, transferein, which carry other molecules into the cell.

Functions Continued… 6. Serum also minimizes mechanical damage and also damage caused by viscosity e.g., shear forces during agitation of suspension cultures. 7. Serum also acts as natural buffering agent and helps in maintaining the pH of the culture media. 8. The serum also provides several minerals, e.g., K+, Na+, Fe2+, Zn2+, etc. 9. Protease inhibitors present in the serum protect cells from proteolysis.

Disadvantages of Serum containing Media Serum may contain inadequate amount of cell specific growth factors and may need to supplement the media or may contain abundance of cytotoxic compounds. It has got high risk of contamination with virus , fungi and mycoplasma. There is no uniformity in the composition of the serum i.e., the exact composition is not known. There is a large variation in serum batch to batch culture

Disadvantages continued.. 5. Serum may inhibit growth of some cell types, e.g., epidermal keratinocytes 6. It interferes with the downstream processing when cell cultures are used for production of biochemical's. 7. The supply of serum is always lower than its demand.

Serum free media As using serum in animal cell culture media has got some disadvantages, to overcome this, serum free media are designed and developed.

Advantages of Serum Free Media The growth can be controlled of the cultured cells as required by changing the composition of the media . Easier downstream processing of products from cultured cells. Toxic effect of serum are avoided. There is no danger of degradation of sensitive proteins by serum proteases.

Disadvantages of serum free media Cell proliferation is very low Cultured cells may need more than one type of media to obtain desired cell culture products. A greater control over the pH, Temperature, etc. is necessary as compared to that with serum containing media. Growth rate and the maximum cell density attained are lower than those with serum containing media.