Cell culture is one of major techniques in the life sciences. It is the general term used for the removal of cells, tissues or organs from an animal or plant and their subsequent placement into an artificial environment conducive to their survival and/or proliferation. Basic environmental requirements for cells to grow optimally are: controlled temperature, substrate for cell attachment, and appropriate growth medium and incubator that maintains correct pH and osmolality. The most important and crucial step in cell culture is selecting appropriate growth medium for the in vitro cultivation. A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms, cells, or small plants. Cell culture media generally comprise an appropriate source of energy and compounds which regulate the cell cycle. A typical culture medium is composed of a complement of amino acids, vitamins, inorganic salts, glucose, and serum as a source of growth factors, hormones, and attachment factors. In addition to nutrients, the medium also helps maintain pH and osmolality.

Animal cells can be cultured either using a completely natural medium or an artificial/synthetic medium along with some natural products.

Natural media consist solely of naturally occurring biological fluids. Natural media are very useful and convenient for a wide range of animal cell culture. The major disadvantage of natural media is its poor reproducibility due to lack of knowledge of the exact composition of these natural media.

Artificial or synthetic media are prepared by adding nutrients (both organic and inorganic), vitamins, salts, O₂ and CO₂ gas phases, serum proteins, carbohydrates, cofactors [1]. Different artificial media have been devised to serve one or more of the following purposes: 1) immediate survival (a balanced salt solution, with specific pH and osmotic pressure); 2) prolonged survival (a balanced salt solution supplemented with various formulation of organic compounds and/or serum); 3) indefinite growth; 4) specialized functions.

Artificial media are grouped into four categories:

Fetal bovine serum is the most common supplement in animal cell culture media. It is used as a low-cost supplement to provide an optimal culture medium. Serum provides carriers or chelators for labile or water-insoluble nutrients, hormones and growth factors, protease inhibitors, and binds and neutralizes toxic moieties.

Presence of serum in the media has many drawbacks and can lead to serious misinterpretations in immunological studies [2, 3]. A number of serum-free media have been developed [4, 5]. These media are generally specifically formulated to support the culture of a single cell type, such as Knockout Serum Replacement and Knockout DMEM from Thermo Fisher Scientific for stem cells, and incorporate defined quantities of purified growth factors, lipoproteins, and other proteins, which are otherwise usually provided by the serum [6]. These media are also referred to as ‘defined culture media’ since the components in these media are known [7, 8].

These media contain contamination-free ultra pure inorganic and organic ingredients, and may also contain pure protein additives, like growth factors [9]. Their constituents are produced in bacteria or yeast by genetic engineering with the addition of vitamins, cholesterol, specific amino acids, and fatty acids [10].

Protein-free media do not contain any protein and only contain non-protein constituents. Compared to serum-supplemented media, use of protein-free media promotes superior cell growth and protein expression and facilitates downstream purification of any expressed product [11-13]. Formulations like MEM, RPMI-1640 are protein-free and protein supplement is provided when required.

Culture media contain a mixture of amino acids, glucose, salts, vitamins, and other nutrients, and available either as a powder or as a liquid form from commercial suppliers [14-18]. The requirements for these components vary among cell lines, and these differences are partly responsible for the extensive number of medium formulations [19]. Each component performs a specific function, as described below:

Regulating pH is critical for optimum culture conditions and is generally achieved by one of the two buffering systems:

In a natural buffering system, gaseous CO₂ balances with the CO₃/HCO₃ content of the culture medium. Cultures with a natural buffering system need to be maintained in an air atmosphere with 5-10% CO₂, usually maintained by an CO₂ incubator. Natural buffering system is low cost and non-toxic [20, 21].

Chemical buffering using a zwitterion, HEPES, has a superior buffering capacity in the pH range 7.2-7.4 and does not require a controlled gaseous atmosphere [22]. HEPES is relatively expensive and toxic at a higher concentration for some cell types. HEPES has also been shown to greatly increase the sensitivity of media to phototoxic effects induced by exposure to fluorescent light [23].

Most of the commercially available culture media include phenol red as a pH indicator, which allows constant monitoring of pH [24]. During the cell growth, the medium changes color as pH is changed due to the metabolites released by the cells. At low pH levels, phenol red turns the medium yellow, while at higher pH levels it turns the medium purple. Medium is bright red for pH 7.4, the optimum pH value for cell culture. However, there are certain disadvantages of using phenol red as described below: 1) Phenol red mimics the action of some steroid hormones, particularly estrogen [25]. Thus it is advisable to use media without phenol red for studies using estrogen-sensitive cells like mammary tissue. 2) Presence of phenol red in some serum-free formulations interferes with the sodium-potassium homeostasis. This effect can be neutralized by the inclusion of serum or bovine pituitary hormone in the medium [26]. 3) Phenol red interferes with detection in flow cytometric studies.

Inorganic salt in the media help to retain the osmotic balance and help in regulating membrane potential by providing sodium, potassium, and calcium ions [27].

Amino acids are the building blocks of proteins, and thus are obligatory ingredients of all known cell culture media. Essential amino acids must be included in the culture media as cells can not synthesize these by themselves. They ae required for the proliferation of cells and their concentration determines the maximum achievable cell density. L-glutamine, an essential amino acid, is particularly important [28]. L-glutamine provides nitrogen for NAD, NADPH and nucleotides and serves as a secondary energy source for metabolism. L-glutamine is an unstable amino acid, that, with time, converts to a form that can not be used by cells, and should thus be added to media just before use [29]. Caution should be used when adding more L-glutamine than is called for in the original medium formulation since its degradation results in the build-up of ammonia, and ammonia can have deleterious effect on some cell lines. L-glutamine concentrations for mammalian cell culture media can vary from 0.68 mM in Medium 199 to 4mM in Dulbecco’s Modified Eagles’s Medium. Invertebrate cell culture media can contain as much as 12.3 mM L-glutamine. Supplements like glutamax are more stable and can replace glutamine for long term culturing of slow cells.

Nonessential amino acids may also be added to the medium to replace those that have been depleted during growth. Supplementation of media with non-essential amino acids stimulates growth and prolongs the viability of the cells.

Carbohydrates in the form of sugars are the major source of energy. Most of the media contain glucose and galactose, however, some contain maltose and fructose.

The most commonly used proteins and peptides are albumin, transferrin, and fibronectin. They are particularly important in serum-free media. Serum is a rich source of proteins and includes albumin, transferrin, aprotinin, fetuin, and fibronectin. Albumin is the main protein in blood acting to bind water, salts, free fatty acids, hormones, and vitamins, and transport them between tissues and cells. The binding capacity of albumin makes it a suitable remover of toxic substances from the cell culture media.

Aprotinin is a protective agent in cell culture systems, stable at neutral and acidic pH and resistant to high temperatures and degradation by proteolytic enzymes. It has the ability to inhibit several serine proteases such as trypsin. Fetuin is a glycoprotein found in fetal and newborn serum at larger concentrations than in adult serum. It is also an inhibitor of serine proteases. Fibronectin is a key player in cell attachment. Transferrin is an iron transport protein that acts to supply iron to the cell membrane.

They are particularly important in serum-free media as they are generally present in serum.

Many vitamins are essential for growth and proliferation of cells. Vitamins cannot be synthesized in sufficient quantities by cells and are therefore important supplements required in tissue culture. Again serum is the major source of vitamins in cell culture, however, media are also enriched with different vitamins making them suitable for a particular cell line. The B group vitamins are most commonly added for growth stimulation.

Trace elements are often supplemented to serum-free media to replace those normally found in serum. Trace elements like copper, zinc, selenium and tricarboxylic acid intermediates are chemical elements that are needed in minute amounts for proper cell growth [30]. These micronutrients are essential for many biological processes, e.g. the maintenance of the functionality of enzymes.

The complete growth media recommended for certain cell lines requires additional components which are not present in the basal media and serum. These components, supplements, help sustain proliferation and maintain normal cell metabolism [31, 32]. Although supplements like hormones, growth factors and signaling substances are required for normal growth of some cell lines, it is always best to take the following precautions: since the addition of supplement can change the osmolality of the complete growth media which can negatively affect the growth of cells, it is always best to recheck the osmolality after supplements are added. For most of the cell lines, optimal osmolality should be between 260 mOSM/kg and 320 mOSM/kg.

Shelf life of the growth media changes after the addition of supplements. Complete media containing protein supplement tend to degrade faster than basal media alone.

Although not required for cell growth, antibiotics are often used to control the growth of bacterial and fungal contaminants [33]. Routine use of antibiotics for cell culture is not recommended since antibiotics can mask contamination by mycoplasma and resistant bacteria [34, 35]. Moreover, antibiotics can also interfere with the metabolism of sensitive cells.

Serum is a complex mix of albumins, growth factors and growth inhibitors [36]. Serum is one of the most important components of cell culture media and serves as a source for amino acids, proteins, vitamins (particularly fat-soluble vitamins such as A, D, E, and K), carbohydrates, lipids, hormones, growth factors, minerals, and trace elements. Serum from fetal and calf bovine sources are commonly used to support the growth of cells in culture [37]. Fetal serum is a rich source of growth factors and is appropriate for cell cloning and for the growth of fastidious cells [38]. Calf serum is used in contact-inhibition studies because of its lower growth-promoting properties. Normal growth media often contain 2-10% of serum. Supplementation of media with serum serves the following functions [39] :

• Serum provides the basic nutrients (both in the solution as well as bound to the proteins) for cells.
• Serum provides several growth factors and hormones involved in growth promotion and specialized cell function.
• It provides several binding proteins like albumin, transferrin, which can carry other molecules into the cell. For example: albumin carries lipids, vitamins, hormones, etc into cells.
• It also supplies proteins, like fibronectin, which promote attachment of cells to the substrate. It also provides spreading factors that help the cells to spread out before they begin to divide.
• It provides protease inhibitors which protect cells from preolysis.
• It also provides minerals, like Na+, K+, Zn2+, Fe2+, etc.
• It increases the viscosity of medium and thus, protects cells from mechanical damages during agitation of suspension cultures.
• It also acts a buffer.

Due to the presence of both growth factors and inhibitors, the role of serum in cell culture is very complex. Unfortunately, in addition to serving various functions, the use of serum in tissue culture applications has several drawbacks [12, 40, 41]. Table 2 shows the advantages and disadvantages of using serum in the media.

Culture medium is available in three forms from commercial suppliers:

1. Powdered form: it needs to be prepared and sterilized by the investigator.
2. Concentrated form: to be diluted by the investigator.
3. Working solution: to be used directly without further manipulation.

Powdered medium is the least expensive but needs to be sterilized [42]. It is advisable to filter sterilize it prior to the addition of serum as the foaming that occurs in the presence of serum denatures the protein. Fetal bovine or horse sera can be added after filtration. Media should always be tested for sterility by placing it in a 37^oC CO₂ incubator for 72 hours prior to utilization to ensure that the lot is contamination-free. Medium should be stored at 4^oC. Since several components of medium are light-sensitive, it should be stored in dark.

The choice of cell culture media is extremely important, and significantly affects the success of cell culture experiments [43]. The selection of the media depends on the type of cells to be cultured and also the purpose of the culture and resources available in the laboratory [44, 45]. Different cell types have highly specific growth requirements, therefore, the most suitable media for each cell type must be determined experimentally [46-48]. In general, it’s always good to start with MEM for adherent cells and RPMI-1640 for suspension cells. Table 3 describes commonly studied cell lines and recommended growth media.

Primary cell culture provides unique and valuable research data, but most of the time cell number is the limitation. For such critical samples, especially from diseased human biopsies, a quality medium is required. Most of the life sciences companies are providing complete and ready to use, fully supplemented conditioned medium. This reduces the risk of contamination as well as save time, labor and money by eliminating the preparation steps and supplementation required. Moreover, all of these media are subjected to comprehensive quality control tests and each lot is routinely tested for growth promotion, absence of cytotoxicity, and physical parameters such as osmolality and pH level. Table 4 describes the recommended media provided by different companies for commonly used primary cells.

Most commonly used culture media include the following and are discussed in detail at Sigma, ATCC, and Life Technologies.

EMEM was among the first widely used media and was formulated by Harry Eagle from a simpler basal medium (BME). EMEM contains balanced salt solution, nonessential amino acids, and sodium pyruvate. It is formulated with a reduced sodium bicarbonate concentration (1500 mg/l) for use with 5% CO₂. Since EMEM is a non-complex medium, it is generally fortified with additional supplements or higher levels of serum making it suitable for a wide range of mammalian cells.

DMEM has almost twice the concentration of amino acids and four times the amount of vitamins as EMEM, as well as ferric nitrate, sodium pyruvate, and some supplementary amino acids. The original formulation contained 1,000 mg/L of glucose and was first reported for culturing embryonic mouse cells. A further variation with 4500 mg/L of glucose has been proved to be optimal for culture of various types of cells. DMEM is a basal medium and contains no proteins or growth promoting agents. Therefore, it requires supplementation to be a “complete” medium. It is most commonly supplemented with 5-10% Fetal Bovine Serum (FBS). DMEM utilizes a sodium bicarbonate buffer system (3.7 g/L) and therefore requires artificial levels of CO₂ to maintain the required pH. Powdered media is formulated without sodium bicarbonate because it tends to gas off in the powdered state. Powdered media requires the addition of 3.7 g/L of sodium bicarbonate upon dissolving it in water. DMEM was used initially for the culture of mouse embryonic stem cells. It has been found to be widely applicable in primary mouse and chicken cells, viral plaque formation and contact inhibition studies.

RPMI-1640 is a general purpose media with a broad range of applications for mammalian cells, especially hematopoietic cells. RPMI-1640 was developed at Roswell Park Memorial Institute (RPMI) in Buffalo, New York. RPMI-1640 is a modification of McCoy’s 5A and was developed for the long-term culture of peripheral blood lymphocytes. RPMI-1640 uses a bicarbonate buffering system and differs from the most mammalian cell culture media in its typical pH 8 formulation. RPMI-1640 supports the growth of a wide variety of cells in suspension and grown as monolayers. If properly supplemented with serum or an adequate serum replacement, RPMI-1640 has a wide range of applications for mammalian cells, including the culture of fresh human lymphocytes, fusion protocols, and growth of hybrid cells.

These were originally developed to support the clonal outgrowth of Chinese hamster ovary (CHO) cells. There has been numerous modifications to the original formulation including Hams’s F-12 medium, a more complex formulation than the original F-10 suitable for serum-free propagation. Mixtures were formulated for use with or without serum supplementation, depending on the type of cells being cultured.

Ham’s F-10: It has been shown to support the growth of human diploid cells and white blood cells for chromosomal analysis.

Ham’s F-12: It has been shown to support the growth of primary rat hepatocytes and rat prostate epithelial cells. Ham’s F-12 supplemented with 25 mM HEPES provides more optimum buffering.

Coon’s modification of Ham’s F-12: It consists of almost two times the amount of amino acids and pyruvate as compared to F-12 and also includes ascorbic acid. It was developed for culturing hybrid cells produced by viral fusion.

DMEM/F12: It is a mixture of DMEM and Ham’s F-12 and is an extremely rich and complex medium. It supports the growth of a broad range of cell types in both serum and serum-free formulations. HEPES buffer is included in the formulation at a final concentration of 15 mM to compensate for the loss of buffering capacity incurred by eliminating serum.

IMDM is a highly enriched synthetic media well suited for rapidly proliferating, high-density cell cultures. IMDM is a modification of DMEM containing selenium, and has additional amino acids, vitamins and inorganic salts as compared to DMEM. It has potassium nitrate instead of ferric nitrate and also contains HEPES and sodium pyruvate. It was formulated for the growth of lymphocytes and hybridomas. Studies have demonstrated that IMDM can support murine B lymphocytes, hemopoietic tissue from bone marrow, B cells stimulated with lipopolysaccharide, T lymphocytes, and a variety of hybrid cells.

Table 5 describes different cells/cell lines which can be cultured using above mentioned media:

The complexity of composition of cell culture media provides many challenges to optimize individual components of media. Most of the classical culture media were devised for small-scale low-density cultures and often require serum as a key nutrient. However, in biotechnology industry where there is a need to sustain high cell densities and increase cellular productivity, development and optimization of culture media is very critical [49]. Typically, media for the biotechnology industry are serum free and have much higher concentration of nutrients than classical media [50, 51]. Optimization of media requires the following parameters to be considered:

The type of product needed will determine the medium optimization strategy.

For the rapid generation of cell numbers, cell growth rate and viability are critical. So, cell culture media should support maximal cell growth and sustain cell viability at increasing cell densities.

For the production of virus, not just high cell densities are required but there must be abundant nutrients in the media to sustain virus replication after infection.

For the production of recombinant protein, high cell density is required. However, nutrients required for the cell growth can compete with those required for production of proteins. It is, therefore, very important to carefully determine the maximum cell densities a given medium can sustain for a required level of productivity. In addition, it is very important to consider that changes to the medium during optimization must not affect product quality.

Different cell lines have different nutritional requirements because of difference in metabolism which dictates media optimization methods. The most common cell lines used in the biotechnology industries are CHO cells, BHK-21, hybridoma cells, myeloma cells, and normal diploid fibroblasts. Certain cell lines have specific nutritional requirements, such as cholesterol for NS0 myeloma cells. Normal diploid fibroblasts require attachment factors to adhere and spread out on a surface for growth. They grow to much lower densities and therefore do not need nutrients in high quantities. Hybridoma cells lines are generally highly dependent on glutamine. They typically lack a stationary phase after reaching a peak cell density and then decline rapidly in viability. Optimization of medium, thus, would reduce decline in viability and improve monoclonal antibody production.

Manufacturing process mode would not only affect the choice of cell culture medium but also approaches to optimization. Different manufacturing processes used are:

Batch Process: A single medium is used to sustain cell growth and productivity. Medium should therefore be rich in nutrients but remain in physiological limits of the cells.

Fed-batch: Several kinds of media are used over the course of the cell culture, depending on the stage of the process. A growth medium is designed in such a way that it has lower nutrient concentrations when cell densities are low during inoculation but maintain high rates of cell growth during culture scale-up and early production. A separate production medium which has increased nutrient concentrations over growth medium can also be used when the culture reaches production stage.

Cell culture media technology has advanced tremendously during the past few decades. Finding a good cell culture medium is very important for the overall performance of cell culture. Today’s challenge is to develop sophisticated media that can be individually optimized for a range of cell cultures. Diversity of cell lines and involvement of large number of media components makes it very difficult. The fact that many of those components are interdependent on others because of the complexity of cellular metabolic pathways adds another layer of complexity.

Labome conducts systematic survey about reagents and instruments cited in formal publications. Labome curated over 750 articles with citations of cell culture media, as of August 2, 2015. Table 6 lists the major types of the media and the main suppliers.

Invitrogen is one of major suppliers of DMEM medium. Invitrogen DMEM media were used to culture COS-1 monkey kidney fibroblast cell line in order to study the effect of the interaction between UBE1L and the PML domain for ISG15ylation on PML/RARalpha [52], to perform heterotopic grafting in order to show that specific myeloid cells derived from the yolk sac [53], to investigate the effect of a C-terminally tethered G protein alpha-subunit on the recycling rate and post-endocytic fate of the beta2AR receptor [54], to culture cells in order to investigate the role of transcription factor Ets-1 in the regulation of Natriuretic Peptide Receptor-A expression [55], to perform cell culture in order to show that natural variation in plants could be induced by chromatin silencing modulation [56], to perform cell culture in order to study the mechanism of the AMPK's regulation towards the circadian clock [57] and many others [56-71, 71-118, 118-156, 156-219, 219-227].

Sigma DMEM media were cited by a number of publications [57, 228-235, 235-249] and [250].

Other suppliers also provided the DMEM media, such as ATCC [251], Biochrom [252], Biological Industries [253], BioWhittaker [254, 255], Caisson labs [256], Cambrex Biosciences [257], Cellgro [241, 258-262], Chemicon [263], Fisher Scientific [264, 265], Hyclone [266-268], Lonza [269, 270], Mediatech [56, 123, 271-274], Nissui Pharmaceutical Co [218, 236], PAA [275, 276], PAN Biotech [277], Peprotech [278], SAFC Biosciences [279], Welgene [280], and Dundee Cell Products [281].

MEM (Minimum Essential Medium) can be used with a variety of suspension and adherent mammalian cells. Invitrogen was also the major supplier of MEM medium. Applications of their products range from ES cell culture to show proper organogenesis needs B-type lamins in mice [168] and T cells culture to confirm Bcl-3 is part of the pathway whereby adjuvants affect T cell lifespans [282], to study of the role of progestin-stimulated rapid PR signaling in the transcriptional regulation of target genes involved in breast cancer cell proliferation [283], as well as many other topics [59, 60, 64, 71, 72, 99, 100, 112, 120, 133, 163, 176, 182, 183, 186, 189, 205, 228, 244, 262, 280, 283, 284, 284-286, 286-288, 288-291, 291, 292, 292, 293, 293-350].

Other MEM medium suppliers were cited as well, including American Type Culture Collection [202], BioWhittaker [351], Gemini Bio-Products [352], HaartBio Ltd [353], Lonza [270, 303, 354], Mediatech [150, 355], Irvine Scientific [349] and Sigma [60, 242, 301, 356-359].

Roswell Park Memorial Institute (RPMI)-1640 medium was originally developed to culture human leukemic cells. Invitrogen RPMI-1640 has been used for a variety of mammalian cells. It was used to culture cells in order to study the role of Bacteroides fragilis in establishing host-microbial symbiosis [360], to study the effect of the interaction between UBE1L and the PML domain for ISG15ylation on PML/RARalpha [52], to culture LNCaP cells in order to prove the CBP in drosophila experimental model system can corepress the transactivation of androgen receptor in pericentric heterochromatin [361], among many other research topics [60, 64, 90, 95, 114, 115, 117, 123, 127, 133, 134, 139, 145, 156, 160, 165, 193, 200, 222, 242, 243, 251, 273, 274, 285, 303, 314, 327, 362-367, 367-374, 374, 375, 375-404].

Sigma RPMI-1640 could be found in other publications [134, 140, 279, 405-414] and [415-417].

Moreover， ATCC [176, 212, 298, 418], Athena Enzyme Systems [166], Biochrom [252], BioWhitaker [255, 419-421], Cambrex [422], Cellgro [332], CRUK [423], HyClone [185, 360, 424-426], Lonza [240, 427], Mediatech [123], Societ Prodotti Antibiotici [428], Nacalai Tesque [218] and US Biological [279] also provided RPMI-1640 media.

DMEM/F12 is a 1:1 mixture of DMEM and Ham's F-12. It is an extremely rich complex medium. Most of the DMEM/F12 media cited in this survey were provided by Invitrogen. They were used to support the growth of a wide range of cell types and study their biological characteristics, such as the regulation of PFK1 glycosylation on cancer cell growth [134], the role of Oct-4 expression in tumor malignancy [429], the role of Vsx2 in mediating mitogen signaling [430], the role of luteinizing hormone signaling in the early activation of the EGF network [71], the effect of topical immunosuppressive agents on the survival of cultivated allo-conjunctival equivalents [431], the role for CFTR in regulating NFkappaB mediated innate immune response [293] and the culture of neuronal progenitor (NP) cells isolated from a human fetal brain [70] and many others [74, 97, 128, 214, 267, 269, 288, 321, 382, 432-446].

Other suppliers also provided the DMEM/F12 medium, such as Sigma [353, 409, 447-449], Kibbutz Beit-Ha'Emek [450], Mediatech [451], STEMCELL Technologies [452], Trace Biosciences [453] and Wako [319].

Ham's F-12 Nutrient Mixture (F-12) has been used for serum-free growth of CHO cultures as well as serum-supplemented growth of other mammalian cells. Invitrogen offered a variety of F-12 modifications for a range of cell culture applications [85, 118, 126, 176, 185, 203, 205, 242].

Besides, products from ATCC [385], BioSource [202], BioWhittaker [255], Gemini Bioproducts [454], Mediatech Inc [254], Roche Diagnostics [325], Sigma [127, 232] and Wako [455] were cited as well.

Neuralbasal medium is a basal medium that meets the special cell culture requirements of post-natal and adult neuronal cells. All the neuralbasal medium cited in the survey were provided by Invitrogen. It was used to grow neuronal cells from hippocampus, cortex and other regions of the brain [217, 256, 311, 323, 455-464].

Schneider's Drosophila medium was originally designed for the growth of S2 cells from the fruit fly, Drosophila melanogaster. Invitrogen [279, 465-469], Sigma [470-473] and other suppliers such as Lonza [474], Serva [475] and US Biological [279] offer the Schneider's Drosophila medium. Another common drosophila media is Gibco Express Five SF Medium [279, 476, 477].

McCoy's 5A medium is a general purpose medium that supports the propagation of many types of cells. Invitrogen provided most of the McCoy's 5A medium in the surveyed cohort [141, 152, 176, 185, 218, 478, 479]. Other suppliers included Cellgro [418], Mediatech [150] and Promocell GmBH [152].

Other media have been cited as well, including Medium YPD [336, 480, 481] for yeast growth, TC-100 insect medium [467, 482, 483] for insect cell cluture, Endothelial cell growth medium-2 (EGM-2) [193, 484-490] for endothelial cell, Medium 199 [56, 260, 368, 491-494], IMDM [362, 423, 495, 496], Terrific Broth medium [124, 480], skeletal muscle cell differentiation medium [101, 497], Shields and Sang insect medium [498, 499], MethoCult medium [129, 500-503], M9 minimal media [297, 504], Mammary Epithelial Growth Medium [126, 159], MCDB 131 medium [94, 505, 506], M2 medium [276, 507-509], Lymphocytes Separation Medium [510, 511], M16 medium [507, 508], keratinocyte growth medium [127, 138], Leibovitz's L-15 Medium [71, 84, 176, 512, 513], Insect Xpress medium [474], Epilife medium supplement [195], ESF 921 growth media [474, 514], Express Five SF Medium [476, 477], 1 ITS liquid media supplement [515], AIMV medium [496], Barbour-Stoenner-Kelly-H (BSK-H) medium [516], BBL Brewers modified thioglycollate medium [517], BGJ medium [133], BioWhittaker Ultraculture medium [122], BMGY media [518], bronchial epithelial cell growth medium [150], Broth Heart Infusion medium [285], Cellgro lymphocyte separation medium [409], CnT07 media [354], EPC medium [519], ESGRO Complete PLUS Clonal Grade Medium [168], Ex-CELL 400 medium [520], explant medium [56], Graces insect cell culture medium [521], HBSS medium [285, 522], HCMTM hepatocyte culture medium [523], Hibernate E media [524], Histopaque density medium [511], Hybridoma SFM media [268], HyQ-SFX insect serum free medium [512], Insect Medium Supplement [525], IPL-41 medium [526], LHC-8 media [59], LHC-9 medium [527], Linsmaier and Skoog (LS) media [528], M17 medium [529], M3:10 media [530], MCDB153 medium [531], Medium 200 [292], Mesenchymal Stem Cell expansion media [267], MesenPro media [532], methionine/cysteine free tissue culture media [533], MSC culture medium [519], N1 growth medium supplement [301], PrEC medium [534], renal Epithelial Basal Medium [152], rich defined medium [535], S2 medium [525], Sabouraud dextrose medium [536], serum-free free-style medium [537], serum-free media containing Neurobasal-A Medium [538], serum-free N2.1 medium [409], SFM4CHO media [539], SFX-Insect Medium [540], skeletal muscle growth medium [280], StemSpan SFEM medium [541], thioglycollate medium [375], T-lymphocyte-conditioned medium [542], VP-SFM medium [363], YNB medium [336], adipocyte differentiation media [348], chondrocyte differentiation media [348], EGM-2 medium [212], M3434 methylcellulose-based medium [543], Mesencult media [348], Murashige and Skoog media [544].