Cell culture is a foundational practice in biology where cells are grown outside their natural environment in a controlled laboratory setting. This technique provides the necessary conditions for cells from an organism to survive and multiply. Scientists use cell culture to study cellular processes, understand disease mechanisms, and develop new treatments, offering precise control over the cellular environment.
Understanding Cell Culture: The Fundamentals
Cell culture involves maintaining cells in an artificial environment that mimics their natural physiological conditions. While applicable to plant and microbial cells, the term often refers to cultivating cells from multicellular eukaryotes, especially animal cells. Growing cells in isolation provides a simplified system to study them without the complexities of an entire organism, observing how they respond to various stimuli or genetic changes.
Cells in culture are categorized into primary cells and cell lines. Primary cells, isolated directly from living tissues like biopsies, closely resemble the original tissue’s characteristics but have a limited lifespan. In contrast, cell lines proliferate indefinitely, either through natural changes or genetic modification. These cell lines, such as HeLa cells, can be passaged over many generations, offering a consistent resource for long-term studies.
Why Cell Culture Matters: Diverse Applications
Cell culture has broad applications across scientific and medical fields, enabling advancements in human health and technology. A significant use is in drug discovery and testing, where cultured cells model new drug candidates’ effectiveness and potential toxicity. Researchers expose cells to compounds to observe effects, identifying promising treatments and understanding their mechanisms. This approach reduces early-stage animal testing and accelerates drug development.
Vaccine production relies on cell culture, as many vaccines require growing viruses in living cells. Cells propagate viruses in large quantities for vaccine creation. Cell culture also plays a role in disease modeling, providing a platform to study complex conditions like cancer or viral infections in a controlled environment. Scientists manipulate cells to mimic disease states, offering insights into disease progression and therapeutic targets.
Beyond drug and vaccine development, cell culture is important for gene therapy research, modifying cells to treat or prevent diseases. It is also used in tissue engineering and regenerative medicine to grow tissues or organs for transplantation or repair. Cell culture offers a humane alternative for cosmetic testing, allowing product safety evaluation without animal involvement, including using reconstructed human skin models.
How Cells Are Grown: Key Requirements
Successful cell culture requires a controlled environment supporting cell survival, growth, and preventing contamination. Sterility is paramount, achieved using laminar flow hoods or biosafety cabinets. These enclosures provide filtered air, minimizing airborne contaminants like bacteria or fungi. All equipment, media, and reagents must also be sterile.
Cells are grown in specialized growth media, supplying necessary nutrients for cellular metabolism and proliferation. This media contains amino acids, carbohydrates (like glucose), vitamins, and inorganic salts. Growth factors, hormones, and serum (often fetal bovine serum) are added for specific cellular activities and beneficial components. A buffering system, often bicarbonate and CO2, maintains the media’s pH within a narrow physiological range, typically 7.2-7.4 for mammalian cells.
Optimal physical conditions are important, especially for mammalian cells thriving at 37°C, mimicking body temperature. CO2 incubators provide this stable temperature and a controlled CO2 concentration, commonly 5%. They also maintain high humidity to prevent media evaporation, ensuring consistent nutrient and salt concentrations. Cells grow either attached to a surface (adherent culture) or suspended freely (suspension culture), depending on cell type and experimental needs.