Cell culture is a vital laboratory technique that involves growing cells in a controlled environment, a practice that dates back to 1907. There are two primary types of cell cultures: primary cultures and secondary cultures. Primary cultures consist of cells directly extracted from tissues, such as skin, kidney, or brain. The process involves dissecting the tissue, breaking down the extracellular matrix, and slicing the tissue into thin sections to isolate the cells. However, primary cultures are challenging to maintain because the cells are sensitive to their environment and typically have a limited lifespan.
To overcome these limitations, researchers developed secondary cultures, which are derived from primary cultures. If primary cells can be kept alive long enough to divide, they can be processed to create cell lines. Cell lines are genetically modified cells that can proliferate indefinitely, making them invaluable for research. Many cell lines originate from cancer cells, which exhibit uncontrolled growth, or from normal cells that have been altered to enable continuous division. Despite their ability to grow indefinitely, cell lines usually undergo around 25 to 40 divisions before they die.
The creation of cell lines is beneficial because it allows researchers to generate large populations of cells from a small initial sample. These cells can be frozen at temperatures as low as -80°C or in liquid nitrogen, preserving them for future use. When thawed, the cells resume their growth cycle, providing a reliable source of cells for experiments.
Maintaining cell cultures requires careful attention to their needs. Cells must be provided with nutrients through a media solution, and they typically grow on flat dishes or in three-dimensional environments that mimic the extracellular matrix. Additionally, cells require specific temperature conditions and gas exchanges, such as oxygen intake and carbon dioxide expulsion, to thrive. This meticulous care is essential for producing a homogeneous cell population, which simplifies experimental procedures.
Research conducted using cell cultures is often referred to as in vitro research, indicating that it occurs outside of a living organism, such as in a plastic dish. However, some biochemists may refer to this work as in vivo research, emphasizing that the cells are living entities. It is advisable to follow the terminology used by your instructor or textbook to avoid confusion.
In summary, cell culture is a foundational technique in biological research, enabling scientists to study cellular processes in a controlled environment. By understanding the nuances of primary and secondary cultures, as well as the requirements for maintaining cell lines, researchers can effectively utilize these tools to advance scientific knowledge.
