While the technology for culturing cells has undergone significant changes—from using manual skilled labor to installing automated systems—the reagents for culturing cells have not changed all that much in the past 50 years. What has changed in the past few years, however, is that cells themselves have become reagents. As with other biochemical reagents, laboratories can now buy cells in bulk and freeze them until needed. This has proved very useful, especially for such applications as high-throughput screening, where having millions of cells available from the same batch from the same vendor has reduced both inter- and intra-variability in assays. Use of frozen cells also eliminates problems associated with human variability, scalability, and homogeneity of cells.
Having a reliable source of cells that perform consistently is very important for most applications, and performance of the cells often depends on the health of the cells. The health of the cells in turn depends on the quality of the cell culture media. Typically, a synthetic basal medium is chosen to meet the nutritional needs of a given cell line. Basal media comprise amino acids, vitamins, inorganic salts, organic compounds, and trace elements needed for cell growth and are usually supplemented with at least 5 percent animal serum.
The synthetic basal media formulations are continually tweaked and combined with various supplements to closely mimic metabolic conditions in vivo. Manufacturers now offer options that are chemically defined, serum free, and optimized specifically for certain cell needs. Sometimes, researchers find that reducing or eliminating serum concentrations leads to increased cell definition, more consistent performance, easier purification and downstream processing, precise evaluations of cellular function, increased growth or productivity, better control over response, and enhanced detection of cellular mediators.
Cell culture reagents are available in both liquid and powder forms to promote attachment and spreading of various cell types and sub culturing adherent cells. A broad range of proteins is available to coat cell culture surfaces to promote cell attachment and monolayer formation. A solution of proteolytic and collagenolytic enzymes can be used to detach cells from tissue culture surface, allowing high plating efficiency. Cell detachment enzymes are also used to create single-cell suspensions from clumped cell cultures for counting cells accurately and detaching cells from primary tissue.
Disassociation reagents can be tailored to passaging and culturing requirements for experimental needs with nonenzymatic formulations for cell dissociation. Non-mammalian- derived solutions for cell detachment also are available. Formulations and media also are customized by vendors for specific applications or cell lines.
In addition, there is a lot of innovation taking place in the creation of cell culture matrices that recapitulate a more physiologically relevant environment. The creation of 3-D cell cultures using complex media and structures like beads rather than a flat plastic surface is an attempt to get closer to replicating the complex organization and function of interacting cells. The ultimate goal is to be able to re-create in vitro an environment that resembles what goes on in vivo.
Tanuja Koppal, PhD, is a freelance science writer and consultant based in Randolph, N.J.
KnockOut Serum Replacement (SR) XenoFree enables the growth and expansion of human embryonic stem cells (hESC) and human induced pluripotent stem (iPS) cells in a cell culture medium containing only human-derived or human recombinant proteins, to facilitate the transition of pluripotent stem cell research from the bench to the clinic.
BioWhittaker® classical and specialty media are known for quality and outstanding selection. These performance tested products are supported by quality systems that meet the stringent requirements of the pharmaceutical industry, and are manufactured with USP grade or equivalent chemical components and ultra-pure, validated water-for-injection (WFI).
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Thermo Fisher Scientific
The Cell Culture Excellence program leverages proven products to support the complete cell culture process: growth and passage; culture and experimentation; characterization and analysis; and reagent and sample storage. Product innovations address key issues such as reliability, reproducibility, scalability, traceability, and security. Each product is designed to be easyto- use, for maximum productivity.
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