Cell culture is the process by which cells grow under controlled conditions, usually outside of their natural environment. Once the cells of interest have been isolated from living tissue, they can subsequently be maintained under carefully controlled conditions. These conditions vary for each cell type, but generally consist of a suitable container with a substrate or medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones and gases (CO2, O2) and regulates the physicochemical environment (pH buffer, osmotic pressure, temperature). Most cells require an artificial surface or substrate (adherent or monolayer culture) while others can be cultured by free-floating in culture medium (suspension culture). The lifespan of most cells is genetically determined, but some cells from cell culture have "transformed" into immortal cells that will reproduce indefinitely if optimal conditions are provided.
In practice, the term "cell culture" now refers to the culture of cells derived from multicellular eukaryotes, especially animal cells, in contrast to other types of culture that also grow cells, such as plant tissue culture, fungal culture and culture. microbiological (of microbes). The historical development and methods of cell culture are closely related to those of tissue culture and organ culture. Viral culture is also related to cells as hosts for viruses.
The laboratory technique of keeping living cell lines (a population of cells descended from a single cell and containing the same genetic makeup) separated from their original tissue source became more robust in the mid-20th century.
The 19th century English physiologist Sydney Ringer developed saline solutions containing sodium, potassium, calcium and magnesium chlorides suitable for keeping an isolated animal heart beat outside the body.  In 1885, Wilhelm Roux removed a portion of the medullary plate from an embryonic chicken and kept it in warm saline for several days, establishing the principle of tissue culture.  Ross Granville Harrison, working at the Johns Hopkins School of Medicine and later at Yale University, published the results of his experiments from 1907 to 1910, establishing the methodology of tissue culture.
Cell culture techniques advanced significantly in the 1940s and 1950s to support research in virology. The cultivation of viruses in cell cultures allowed the preparation of purified viruses for the manufacture of vaccines. The injectable polio vaccine developed by Jonas Salk was one of the first products to be mass produced using cell culture techniques. This vaccine was made possible by the cell culture research of John Franklin Enders, Thomas Huckle Weller, and Frederick Chapman Robbins, who received the Nobel Prize for their discovery of a method of growing the virus in monkey kidney cell cultures.