Eagle’s Minimum Essential Medium (EMEM) is a widely used cell culture medium developed by Harry Eagle in the 1950s. EMEM was designed to provide a balanced mixture of nutrients, vitamins, and salts required for the growth and maintenance of various mammalian cell lines in vitro. It was one of the first widely adopted media formulations and has since been modified and adapted for different cell types and research applications.

The primary components of EMEM include:

1. Inorganic salts: These provide essential ions for cellular function, including sodium, potassium, calcium, magnesium, and chloride.
2. Carbohydrates: Glucose is the primary energy source for cells and is included in EMEM to support cellular metabolism.
3. Amino acids: EMEM contains a mixture of essential and non-essential amino acids that are necessary for protein synthesis and other cellular functions.
4. Vitamins: A range of vitamins is included in the medium to support various cellular processes, such as metabolism, redox reactions, and cofactor synthesis.
5. Buffering agents: EMEM typically contains bicarbonate or HEPES as a buffering agent to maintain the pH of the medium under cell culture conditions.

EMEM can be supplemented with additional components to optimize the growth and maintenance of specific cell lines or experimental conditions, including:

1. Serum: Fetal bovine serum (FBS) or other animal sera are commonly added to EMEM to provide additional nutrients, growth factors, and hormones. The serum concentration may vary depending on the specific cell line or experimental setup, but typically ranges from 5-20%.
2. Antibiotics: To prevent bacterial contamination, antibiotics such as penicillin and streptomycin can be added to the medium.
3. L-glutamine: Some formulations of EMEM do not include L-glutamine, which is an essential nutrient for many cell lines. If needed, L-glutamine can be supplemented at a concentration of 2-4 mM.
4. Additional supplements: Some cell lines may require specific growth factors or other supplements for optimal growth and maintenance.

When using EMEM for cell culture, it is essential to follow aseptic techniques and maintain the appropriate environmental conditions, such as temperature, humidity, and CO2 levels. Always consult the specific requirements for your cell line and adjust the medium components and conditions as needed.