In
cell culture biology, confluence refers to the percentage of the surface of a
culture dish that is covered by adherent
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
. For example, 50 percent confluence means roughly half of the surface is covered, while 100 percent confluence means the surface is completely covered by the cells, and no more room is left for the cells to grow as a
monolayer A monolayer is a single, closely packed layer of atoms, molecules, or cells. In some cases it is referred to as a self-assembled monolayer. Monolayers of layered crystals like graphene and molybdenum disulfide are generally called 2D materials.
...
. The cell number refers to, trivially, the number of cells in a given region.
Impact on research
Many cell lines exhibit differences in growth rate or gene expression depending on the degree of confluence. Cells are typically
passaged before becoming fully confluent in order to maintain their
proliferation
Proliferation may refer to:
Weapons
*Nuclear proliferation, the spread of nuclear weapons, material, and technology
*Chemical weapon proliferation, the spread of chemical weapons, material, and technology
* Small arms proliferation, the spread of ...
phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological prop ...
. Some cell types are not limited by
contact inhibition In cell biology, contact inhibition refers to two different but closely related phenomena: contact inhibition of locomotion (CIL) and contact inhibition of proliferation (CIP). CIL refers to the avoidance behavior exhibited by fibroblast-like cells ...
, such as
immortalized cells, and may continue to divide and form layers on top of the parent cells. To achieve optimal and consistent results, experiments are usually performed using cells at a particular confluence, depending on the cell type. Extracellular export of cell free material is also dependent on the cell confluence .
Estimation
Rule of thumb
Comparing the amount of space covered by cells with unoccupied space using the naked eye can provide a rough estimate of confluency.
Hemocytometer
A
hemocytometer
The hemocytometer (or haemocytometer) is a counting-chamber device originally designed and usually used for counting blood cells.
The hemocytometer was invented by Louis-Charles Malassez and consists of a thick glass microscope slide with a ...
can be used to
count cells, giving the cell number.
References
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Cell culture