Amino acids: They are the basic raw materials for cells to synthesize proteins. Generally, 20 essential amino acids are included, such as alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, etc. Among them, glutamine is an important energy source and nitrogen source for cells, being crucial for cell growth and metabolism.
Carbohydrates: They mainly provide energy for cells. Common ones include glucose, ribose, deoxyribose, etc. Glucose is the primary carbon source and energy source in most cell culture media. Cells break it down through glycolysis and the tricarboxylic acid cycle to generate energy for cell metabolism and growth.
Vitamins: They play an important role as coenzymes in the metabolic processes of cells. Examples include vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B6, vitamin B12, pantothenic acid, folic acid, biotin, nicotinamide, etc. The lack of these vitamins may affect the growth and metabolism of cells.
Inorganic salts
Major ions: These include sodium ions (Na⁺), potassium ions (K⁺), calcium ions (Ca²⁺), magnesium ions (Mg²⁺), chloride ions (Cl⁻), phosphate ions (PO₄³⁻), and bicarbonate ions (HCO₃⁻), etc. They are essential for maintaining the osmotic pressure, acid – base balance, and normal physiological functions of cells. For instance, sodium and chloride ions are the main ions maintaining the osmotic pressure of extracellular fluid, while potassium ions are important for maintaining the osmotic pressure of intracellular fluid and the excitability of cells.
Trace elements: Such as iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), etc. Although cells have extremely low requirements for them, they are components or activators of many enzymes and proteins, and play an important role in regulating processes such as cell growth, proliferation, and differentiation.
Special additives
Serum: It usually comes from cattle, horses, humans, etc., such as fetal bovine serum. Serum contains various nutrients and bioactive substances such as growth factors, hormones, and carrier proteins, which can promote cell growth, proliferation, and adhesion. However, the composition of serum is complex, and there may be differences between different batches, which may affect experimental results.
Growth factors: Such as epidermal growth factor (EGF), fibroblast growth factor (FGF), etc. They can promote cell proliferation, differentiation, migration, and other processes, and are very important for culturing specific types of cells and maintaining the specific functions of cells.
Antibiotics: To prevent contamination by microorganisms such as bacteria and fungi during cell culture, antibiotics such as penicillin, streptomycin, and amphotericin B are often added. However, long – term use of antibiotics may lead to drug resistance in cells or have an adverse impact on cell growth, so it should be avoided when not necessary.
Other components
Buffering substances: To maintain the pH stability of the cell culture environment, buffering substances are usually added to the medium, such as HEPES (4 – (2 – hydroxyethyl) – 1 – piperazineethanesulfonic acid) and phosphate – buffered saline. HEPES can maintain good buffering capacity within a relatively wide pH range. It can keep the medium at a relatively stable pH value even when the cells produce acidic substances during metabolism.
Phenol red: It is often used as a pH indicator in the medium. Its color changes with the pH value. Generally, it is red at pH 7.4, turns yellow when the medium becomes more acidic, and turns purple when the medium becomes more alkaline. This allows experimenters to visually judge the pH change of the medium and adjust the culture conditions in a timely manner.
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