Common cell culture refers to the routine laboratory techniques and procedures used to maintain and grow cells under controlled conditions. Cell culture is an essential tool in various fields, such as molecular and cell biology, genetics, pharmacology, and tissue engineering. The cells used for cell culture can be derived from animals, plants, or microorganisms, and are often referred to as cell lines.
Here are some key aspects of common cell culture:
- Cell culture media: Cells are grown in specialized culture media that contain essential nutrients, such as amino acids, vitamins, minerals, and growth factors. The most commonly used media for animal cells include Dulbecco’s Modified Eagle Medium (DMEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and Ham’s F-12 medium.
- Sterile technique: Sterility is crucial to prevent contamination of the cell culture with unwanted microorganisms, such as bacteria, fungi, or mycoplasma. Researchers use aseptic techniques, including the use of laminar flow hoods, sterile pipettes, and other sterile equipment, to minimize the risk of contamination.
- Incubation conditions: Most cells require a controlled environment with specific temperature, humidity, and gas (CO2) levels to grow and proliferate. Typically, mammalian cells are incubated at 37°C with 5% CO2 in a humidified incubator.
- Passaging cells: As cells grow, they will eventually become overcrowded, which can lead to changes in their growth rates and gene expression profiles. To avoid this, cells are routinely passaged or subcultured by detaching them from the growth surface, diluting them, and transferring them to fresh culture vessels with new media.
- Cell counting and viability: To monitor cell growth and determine the optimal time for passaging or experimental treatments, cells are often counted using a hemocytometer or an automated cell counter. Viability is assessed by staining the cells with trypan blue, which is taken up only by dead cells, or by using other viability assays.
Some commonly used cell lines in research include:
- HeLa cells: Derived from cervical cancer cells, these are the first human immortalized cell line, established in 1951.
- HEK293 cells: A human embryonic kidney cell line widely used for protein expression and gene transfection studies.
- NIH/3T3 cells: A mouse embryonic fibroblast cell line often used to study cell transformation and oncogene function.
- COS-7 cells: Derived from African green monkey kidney cells, these are commonly used for transient protein expression and production of recombinant viruses.
- Jurkat cells: A human T-lymphocyte cell line used for immunological and signal transduction studies.
Each cell line may have specific growth requirements and characteristics, so researchers must carefully select the most appropriate cell line for their experiments.