Cultured cells are fundamental tools in modern biological research, representing living cells grown outside of their original organism in a laboratory setting. This process, known as cell culture, involves isolating cells from tissue and maintaining them under highly controlled, artificial conditions. The technique allows scientists to study cellular behavior, function, and interactions in a simplified environment. By providing a consistent and reproducible model system, cultured cells have become the foundation for advancements across medicine, biotechnology, and pharmacology.
How Cells Are Grown Outside the Body
Culturing cells requires recreating a physiological environment within a laboratory vessel. This artificial environment is maintained using specialized equipment, primarily an incubator, which precisely controls both temperature and gas composition. Most mammalian cells thrive at a temperature of 37 degrees Celsius, which mimics the core body temperature of their host organism. The incubator atmosphere is typically enriched with five to ten percent carbon dioxide, which is necessary to stabilize the pH of the liquid growth medium that bathes the cells.
The liquid growth medium is a nutrient-rich solution designed to sustain cell life, containing essential components such as amino acids, carbohydrates, vitamins, and inorganic salts. Growth factors and hormones are also included to stimulate cell division and function. Often, a supplement like fetal bovine serum is added to provide a complex mixture of these necessary proteins. Maintaining a sterile environment is paramount, requiring researchers to employ aseptic techniques to prevent contamination by bacteria, fungi, or other microorganisms that could quickly outgrow and destroy the delicate cell population.
Categories of Cultured Cells
Cells are broadly categorized based on their origin and lifespan, which dictates their utility for specific experiments. Primary cell cultures are derived directly from living tissues and retain biological characteristics of the original tissue, offering high physiological relevance. However, these cells have a limited lifespan and will cease dividing after a finite number of population doublings, a process known as senescence.
Continuous or immortalized cell lines have acquired the ability to proliferate indefinitely. This unlimited growth capacity often results from a natural mutation, such as in cancer cells like the HeLa line, or through deliberate genetic modification. Immortalized lines provide consistency and are highly scalable, though they may have lost some of the specialized features of their tissue of origin. Cell cultures are also described by how they grow, with adherent cultures needing to attach to a surface, while suspension cultures grow free-floating in the medium.
Cultured Cells in Disease Modeling and Drug Development
Cultured cells are experimental models, allowing scientists to study human health and disease. Researchers use specific cell lines to create disease models, such as culturing tumor cells to investigate the mechanisms of cancer progression or neurons to study neurological disorders like Alzheimer’s disease. These models enable the systematic manipulation of cellular processes to identify new therapeutic targets.
Cell culture is used for high-throughput screening in drug development, where thousands of new chemical compounds can be rapidly tested for efficacy and potential toxicity. By exposing cultured human cells to various drug candidates, researchers can quickly narrow down the most promising molecules before moving to more complex testing phases. Recent advances include the use of three-dimensional (3D) cultures and organoids, which better mimic the natural environment of human organs, offering more predictive results.
The technique also supports personalized medicine by allowing the growth of a patient’s own cells, such as immune cells or tumor cells, in the laboratory. Testing different treatments directly on these patient-derived cells can help predict how an individual’s body will respond to a specific therapy. Using these cell models improves the accuracy of preclinical drug testing, helping to reduce the high failure rate of new drugs in later clinical trials.
The Role of Cell Culture in Modern Therapeutics
Cell culture is a major engine of the biotechnology industry, enabling the large-scale manufacture of complex biological medicines. Many therapeutic proteins, including monoclonal antibodies used to treat cancers and autoimmune disorders, are produced by genetically engineered mammalian cells grown in vast bioreactors. These cultured cells act as tiny biological factories, synthesizing these intricate molecules with the necessary modifications.
The production of many modern vaccines relies on cell culture technology, particularly for viral vaccines. Viruses, which cannot replicate on their own, are grown by infecting healthy host cells in a culture dish, allowing the virus to multiply to sufficient quantities for vaccine preparation. The polio, measles, mumps, and rubella vaccines, as well as many influenza vaccines, are manufactured using this cell culture-based approach.
Cultured cells are directly used in cell-based therapies to treat disease. CAR T-cell therapy is a prominent example, where a patient’s own T-cells are harvested, genetically modified in culture to target cancer cells, and then expanded before being re-infused into the patient. Cultured stem cells are also being explored for regenerative medicine, offering the potential to repair or replace damaged tissues and organs.