The components of cell culture medium usually include the following categories:

Nutritional Components

• Amino Acids: They are the basic raw materials for cells to synthesize proteins. Different cells have different requirements for amino acids. Generally, they include essential amino acids and non-essential amino acids, such as glycine, alanine, valine, leucine, etc.
• Monosaccharides: They provide an energy source for cells. Commonly used ones include glucose, galactose, etc. Cells break down monosaccharides through pathways such as glycolysis and the tricarboxylic acid cycle to generate energy (ATP) for cellular metabolic activities.
• Vitamins: They play a role in regulating metabolism and acting as coenzymes in cell metabolism. For example, the B vitamin group (including B1, B2, B6, B12, etc.), folic acid, biotin, etc., are of great significance for cell growth, differentiation, and function maintenance.
• Inorganic Ions: They include macronutrients and micronutrients. Macronutrients such as sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), chlorine (Cl⁻), etc., and micronutrients such as iron (Fe²⁺/Fe³⁺), zinc (Zn²⁺), copper (Cu²⁺), manganese (Mn²⁺), selenium (Se²⁻), etc. They participate in processes such as osmotic pressure regulation, enzyme activity regulation, and signal transduction in cells.

Growth Factors and Hormones

• Growth Factors: They are a class of proteins or polypeptides that can promote cell growth, proliferation, and differentiation. For example, epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), etc. Different growth factors have specific effects on different types of cells.
• Hormones: The growth and functions of some cells require the regulation of hormones. For example, insulin can promote the uptake and utilization of glucose by cells, and glucocorticoids such as hydrocortisone can regulate cell metabolism and immune functions.

Buffer Systems

• Sodium Bicarbonate/CO₂ Buffer System: It is one of the most commonly used buffer systems in cell culture medium. By adjusting the concentration of sodium bicarbonate in the medium and the partial pressure of CO₂, the pH value of the medium is maintained within a suitable range, usually around 7.2 to 7.4.
• HEPES Buffer: It is a non-volatile buffer. When the CO₂ supply is insufficient or a more stable pH value is required in the cell culture environment, it can effectively buffer within a wide pH range and keep the pH of the medium stable.

Other Additives

• Serum: It is one of the most important additives in cell culture medium. It contains rich nutritional components, growth factors, hormones, binding proteins, etc., and can promote cell growth and proliferation. Commonly used sera include fetal bovine serum (FBS), calf serum, etc. However, serum also has some limitations, such as complex composition and large batch-to-batch variations.
• Proteins and Peptides: Such as albumin, transferrin, etc. Albumin can act as a carrier protein, binding with fatty acids, hormones, etc., to regulate their transport and metabolism within cells. Transferrin is responsible for transporting iron ions to meet the iron requirements of cells.
• Antibiotics: In order to prevent the contamination of bacteria, fungi and other microorganisms during the cell culture process, appropriate amounts of antibiotics are usually added to the medium, such as penicillin, streptomycin, gentamicin, etc. However, attention should be paid to the concentration and types of antibiotics used to avoid adverse effects on cells.