DEVELOPMENT OF MEDIA FOR ANIMAL TISSUE
CULTURE
Initially the attempt to culture
(animal) cells was performed in natural media based on tissue extracts and body
fluids, such as chick embryo extract, lymph, serum etc. With the propagation of
cell lines, the demand for larger amounts of a medium of more consistent
quality led to the introduction of chemically defined media based on analyses
of body fluids and nutritional biochemistry. Eagle’s Basal Medium and subsequently,
Eagle’s Minimal Essential Medium (MEM) became widely used mediums, these were supplemented
with horse, human, or calf serum, protein hydrolysates and extracts from embryo.
As more continuous cell lines became available (HeLa, L929 cells etc.), it was assumed
that these media were perfect and adequate for most of these cell lines, and
most of the later developments were aimed to replace serum, optimizing media for
different cell types (e.g., RPMI 1640 for lymphoblastoid cell lines), or
modifying for specific conditions (e.g., Leibovitz L15 to eliminate the need
for adding CO2 and NaHCO3).
Isolation and propagation of cells
of a specific cell line may require a selective serum-free medium, whereas cells
grown for the formation of products, as hosts for viral propagation, or for
non-cell-specific molecular studies rely mainly on Eagle’s MEM, Dulbecco’s modification
of Eagle’s medium, DMEM or even RPMI 1640, supplemented with serum. However,
many industrial-scale production techniques now use serum-free media, to
facilitate downstream processing and reduce the risk of adventitious infectious
agents. A popular compromise for many laboratories is a mixture of a complex
medium, such as Ham’s F12 with higher amino acid and vitamin concentrations,
such as DMEM. This alternative may not be always acceptable but it generates a
useful and all-purpose medium for primary culture as well as cell line
propagation.
We will study the different types
of media in our next post.
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