Cultured cells are cells that are isolated from living organisms and grown under controlled conditions in a laboratory. Cell culture is a widely used technique in biological research, drug development, and regenerative medicine. It allows scientists to study cellular processes, gene expression, and protein functions, as well as to test the effects of drugs and other compounds on cells.
There are two main types of cell cultures:
- Primary cell cultures: Primary cells are isolated directly from the tissue of an organism and have a limited lifespan in culture. These cells maintain many of the characteristics of the original tissue, making them valuable for studying specific cell types, functions, and responses. However, primary cells can be more challenging to culture and maintain than immortalized cell lines.
- Immortalized cell lines: Immortalized cells are derived from primary cells that have been genetically altered or have undergone spontaneous mutations, allowing them to divide indefinitely. These cells have lost some of the characteristics of the original tissue, but they offer a stable, continuous source of cells for research. Immortalized cell lines are often easier to culture and maintain than primary cells, but they may not fully represent the behavior of normal cells in vivo.
Cultured cells are maintained in a growth medium, which provides the necessary nutrients and environmental conditions for their survival and proliferation. The medium typically contains a mixture of salts, sugars, amino acids, vitamins, and growth factors, as well as a source of protein, such as fetal bovine serum. Cells are cultured in an incubator that maintains a controlled environment with optimal temperature, humidity, and gas concentrations (usually 37°C, high humidity, and 5% CO₂).
There are several techniques for culturing cells, including:
- Adherent cultures: Cells that attach to the surface of culture vessels, such as plastic or glass flasks, dishes, or multi-well plates. Adherent cultures are commonly used for fibroblasts, epithelial cells, and some cancer cell lines.
- Suspension cultures: Cells that grow in suspension without attaching to a surface. Suspension cultures are commonly used for hematopoietic cells, such as lymphocytes and some cancer cell lines.
- Three-dimensional (3D) cultures: Cells that grow in a 3D environment, such as a scaffold or hydrogel, more closely mimicking the in vivo conditions. 3D cultures can provide more physiologically relevant results compared to 2D cultures but may be more challenging to maintain and analyze.
Cell culture techniques have advanced significantly over the years, allowing scientists to study cells in ways that were not possible before. However, it is essential to maintain strict aseptic techniques and monitor cell health to ensure the quality and reliability of cultured cells in research.