Final answer:
Primary cell culture refers to the growth of cells directly extracted from animal tissues, used for biomedical research and production of medical products. These cultures require a solid surface for cell growth and undergo contact inhibition, limiting their lifespan. In contrast, continuous cell lines, such as the HeLa cell line, can be subcultured indefinitely.
Step-by-step explanation:
Primary Cell Culture
A primary cell culture involves the initial growth of cells taken directly from animal organs or tissues. To start a primary culture, cells are separated from their tissue matrix using mechanical methods like scraping or mincing, or enzymatic methods involving trypsin or collagenase. These isolated cells are then placed in a liquid culture medium inside a Petri dish or tissue culture flask, providing a solid surface like glass or plastic necessary for their attachment and proliferation.
Primarily cultured cells retain many of the characteristics of the original tissue, including their genetic makeup and biochemical functions. This is useful for studying in vivo conditions in a controlled environment. However, these cultures have a limited lifespan and tend to stop dividing when cell-to-cell contact occurs, termed contact inhibition. To sustain growth, the cells must be periodically subcultured by transferring them to new vessels with fresh medium.
In contrast to primary cell cultures, continuous cell lines can be maintained over an indefinite number of passages. These lines, often derived from tumors or transformed cells, exhibit differences such as the lack of anchorage dependency and contact inhibition, allowing them to grow in denser formations. One famous example of a continuous cell line is the HeLa cell line, which was instrumental in establishing the field of tissue culture.
Applications and Importance of Primary Cell Cultures
- Primary cell cultures are used in various biomedical research, such as studying drug metabolism, which closely mimics in vivo conditions.
- They are essential in the production of medical products like vaccines, antibodies, and hormones, as well as in drug potency testing.
- Cell sorting and subculturing techniques are necessary to transition from primary cultures to secondary and continuous cell lines.