The requirements of different cell lines for culture media vary significantly, mainly in the following aspects

I. Nutritional Components

1. Requirements for Amino Acids
   • Different cell lines have different requirements for the types and quantities of amino acids. For example, some rapidly – proliferating tumor cell lines, such as HeLa cells (a human cervical cancer cell line), have a large demand for various essential amino acids because they need a large amount of amino acids to synthesize proteins during rapid growth. However, some normal cell lines with relatively slow growth have a relatively lower demand for amino acids. In addition, some special cell lines may have specific requirements for particular non – essential amino acids. For example, some neural cell lines may require a relatively large amount of glycine to maintain normal physiological functions.
2. Requirements for Vitamins
   • Cell lines also have different requirements for vitamins. For example, when culturing epithelial cell lines, the presence of vitamin A is very important for cell differentiation and maintaining a normal epithelial structure. Some fibroblast cell lines may have a higher demand for vitamin C because vitamin C is involved in the synthesis of extracellular matrix and helps maintain the function of fibroblasts.
3. Requirements for Growth Factors
   • Different cell lines rely on different growth factors to promote growth and proliferation. For example, endothelial cell lines usually require vascular endothelial growth factor (VEGF) to maintain their growth and angiogenesis ability. Epidermal cell lines benefit from epidermal growth factor (EGF), which can stimulate the proliferation and differentiation of epidermal cells. Some stem cell lines even require the synergistic action of multiple growth factors. For example, neural stem cells may require basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) to maintain their self – renewal and multi – directional differentiation abilities.

II. Physicochemical Properties

1. Requirements for pH Value
   • Each cell line has its suitable pH range. For example, most mammalian cell lines grow well in an environment with a pH value of 7.2 – 7.4. However, some special cell lines may have different pH preferences. For example, some plant cell lines can grow within a wide pH range but prefer a slightly acidic environment with a pH value of 5.5 – 6.5.
2. Requirements for Osmotic Pressure
   • Cell lines have different tolerances to the osmotic pressure of culture media. Generally, human cell lines are adapted to an environment similar to the osmotic pressure of human plasma (about 280 – 320 mOsm/L). However, cell lines derived from marine organisms, such as some fish cell lines, which have evolved in the high – salt marine environment, can tolerate higher osmotic pressure, and their suitable osmotic pressure may be around 350 – 400 mOsm/L.

III. Requirements for Serum

1. Dependence on Serum
   • Different cell lines have greatly different requirements for serum. Some cell lines, such as the common CHO cells (Chinese hamster ovary cells), grow vigorously in media containing an appropriate amount of fetal bovine serum (FBS). Various growth factors, hormones, and nutrients in the serum can meet the growth requirements of CHO cells. However, with the development of cell culture technology, some cell lines have been able to adapt to serum – free media. For example, some hybridoma cell lines can grow in serum – free media after acclimatization, which can avoid batch – to – batch variations and potential contamination risks brought by serum.

IV. Requirements for Special Substances

1. Adhesion Factors
   • For adherent cell lines, such as fibroblast and epithelial cell lines, the culture media need to contain adhesion factors. These cells need to attach to the surface of culture vessels during growth, and adhesion factors (such as fibronectin, collagen, etc.) can promote cell adhesion and spreading. If adhesion factors are lacking, these cells may not grow normally and may even undergo apoptosis.
2. Substances for Inducing Differentiation
   • Some stem cell lines and precursor cell lines need to add substances for inducing differentiation during the culturing process. For example, when culturing mesenchymal stem cells, if they are to be induced to differentiate into osteoblasts, substances such as dexamethasone, β – glycerophosphate, and ascorbic acid usually need to be added to the culture media; if they are to be induced to differentiate into adipocytes, substances such as insulin, dexamethasone, and 3 – isobutyl – 1 – methylxanthine (IBMX) need to be added.

These different requirements of different cell lines for culture media determine that in the process of cell culture, it is necessary to select appropriate culture media according to the characteristics of cells to ensure that cells can grow, proliferate, and function normally.