Editing Incubator (culture)

{{short description|Device used to grow and maintain microbiological cultures or cell cultures}}
[[File:Binder CB 210 incubator interior.jpg|thumb|right|Interior of a [[Carbon dioxide|CO<sub>2</sub>]] incubator used in [[cell culture]]|317x317px]]

An '''incubator''' is a device used to grow and maintain [[microbiological culture]]s or [[cell culture]]s. The incubator maintains optimal [[temperature]], [[humidity]] and other conditions such as the CO<sub>2</sub> and [[oxygen]] content of the atmosphere inside. Incubators are essential for much experimental work in [[cell biology]], [[microbiology]] and [[molecular biology]] and are used to culture both [[bacteria]]l and [[Eukaryote|eukaryotic]] cells.

An incubator is made up of a chamber with a regulated [[temperature]]. Some incubators also regulate [[Relative humidity|humidity]], gas composition, or ventilation within that chamber.

The simplest incubators are insulated boxes with an adjustable heater, typically going up to {{convert|60|to|65|C|F}}, though some can go slightly higher (generally to no more than 100&nbsp;°C). The most commonly used temperature both for bacteria such as the frequently used [[Escherichia coli|E. coli]] as well as for mammalian cells is approximately [[Human body temperature|37 °C]] (99&nbsp;°F), as these organisms grow well under such conditions. For other organisms used in biological experiments, such as the budding yeast [[Saccharomyces cerevisiae]], a growth temperature of {{convert|30|°C|°F|abbr=on}} is optimal.

More elaborate incubators can also include the ability to lower the temperature (via refrigeration), or the ability to control humidity or [[carbon dioxide|CO<sub>2</sub>]] levels. This is important in the cultivation of mammalian cells, where the relative [[humidity]] is typically >80% to prevent evaporation and a slightly acidic [[pH]] is achieved by maintaining a CO<sub>2</sub> level of 5%.[[File:Bacteriological incubator.jpg|thumb|right|A Bacteriological incubator|185x185px]]

== History of the laboratory incubator ==

From aiding in hatching chicken eggs to enabling scientists to understand and develop vaccines for deadly viruses, the laboratory incubator has seen numerous applications over the thousands of years it has been in use. The incubator has also provided a foundation for medical advances and experimental work in cellular and [[molecular biology]].

While many technological advances have occurred since the primitive incubators first used in ancient Egypt and China, the main purpose of the incubator has remained unchanged: to create a stable, controlled environment conducive to research, study, and cultivation.

=== The earliest incubators ===
The [[Egyptian egg oven|earliest incubators]] were invented thousands of years ago in ancient Egypt and China, where they were used to keep chicken eggs warm.<ref name=":0">Paniago, Marcelo. [https://web.archive.org/web/20191118000309/https://pdfs.semanticscholar.org/2279/f8e45d61fe90c68bed9c554c42c2bca4565a.pdf "Artificial Incubation of Poultry Eggs - 3,000 Years of History -", CEVA Sante Animale, Malaysia, September 2005, Retrieved on 29 October 2018]</ref> Use of incubators revolutionized food production, as it allowed chicks to hatch from eggs without requiring that a hen sit on them, thus freeing the hens to lay more eggs in a shorter period of time. Both early Egyptian and Chinese incubators were essentially large rooms that were heated by fires, where attendants turned the eggs at regular intervals to ensure even heat distribution.

=== In the 16th and 17th century ===
[[File:Old Réaumur scale thermometer - IMG 0983.JPG|thumb|188x188px|Reaumur thermometer]]
The incubator received an update in the 16th century when Jean Baptiste Porta drew on ancient Egyptian design to create a more modern egg incubator. While he eventually had to discontinue his work due to the Spanish Inquisition, [[René Antoine Ferchault de Réaumur|Rene-Antoine Ferchault de Reaumur]] took up the challenge in the middle of the 17th century.<ref>{{Cite web|url=https://www.encyclopedia.com/plants-and-animals/agriculture-and-horticulture/agriculture-general/incubator|title=Incubator {{!}} Encyclopedia.com|website=www.encyclopedia.com|access-date=2019-11-18}}</ref> Reaumur warmed his incubator with a wood stove and monitored its temperature using the Reaumur thermometer, another of his inventions.

=== In the 19th century ===
In the 19th century, researchers finally began to recognize that the use of incubators could contribute to medical advancements. They began to experiment to find the ideal environment for maintaining cell culture stocks. These early incubators were simply made up of bell jars that contained a single lit candle. Cultures were placed near the flame on the underside of the jar's lid, and the entire jar was placed in a dry, heated oven.
[[File:Incubatrice di Hess.jpg|thumb|Incubator invented by Hess]]
In the late 19th century, doctors realized another practical use for incubators: keeping premature or weak infants alive. The first infant incubator, used at a women's hospital in Paris, was heated by [[kerosene lamp]]s. Fifty years later, [[Julius Hess|Julius H. Hess]], an American physician often considered to be the father of neonatology, designed an electric infant incubator that closely resembles the infant incubators in use today.<ref>{{Cite journal|last=Hess|first=Julius H.|title=An Electric-Heated Water-Jacketed Infant Incubator and Bed|date=1915-03-27|url=https://jamanetwork.com/journals/jama/fullarticle/440537|journal=Journal of the American Medical Association|language=en|volume=LXIV|issue=13|pages=1068–1069|doi=10.1001/jama.1915.25710390003011c|issn=0002-9955}}</ref>

=== In the 20th century ===
[[File:Shaking incubator for culture tubes.jpg|thumb|194x194px|Shaking incubator]]
The next innovation in incubator technology came in the 1960s, when the CO<sub>2</sub> incubator was introduced to the market.<ref>{{Cite web|url=http://www.biocompare.com/Editorial-Articles/177091-Improvements-in-CO2-Incubators-for-Cell-Cultures/|title=Improvements in CO2 Incubators for Cell Cultures|website=www.biocompare.com|language=en|access-date=2019-12-02}}</ref> Demand came when doctors realized that they could use CO<sub>2</sub> incubators to identify and study pathogens found in patients' bodily fluids. To do this, a sample was harvested and placed onto a sterile dish and into the incubator. The air in the incubator was kept at 37 degrees Celsius, the same temperature as the human body, and the incubator maintained the atmospheric carbon dioxide and nitrogen levels necessary to promote cell growth.

At this time, incubators also began to be used in [[genetic engineering]]. Scientists could create biologically essential proteins, such as insulin, with the use of incubators. Genetic modification could now take place on a molecular level, helping to improve the nutritional content and resistance to pestilence and disease of fruits and vegetables.

=== Today ===

Incubators serve a variety of functions in a scientific lab. Incubators generally maintain a constant temperature, however additional features are often built in. Many incubators also control humidity. Shaking incubators incorporate movement to mix cultures. Gas incubators regulate the internal gas composition. Some incubators have a means of circulating the air inside of them to ensure even distribution of temperatures. Many incubators built for laboratory use have a redundant power source, to ensure that power outages do not disrupt experiments. Incubators are made in a variety of sizes, from tabletop models, to warm rooms, which serve as incubators for large numbers of samples.

==See also==
{{Portal|Biology}}
* [[Egyptian egg oven]]

==References==
{{reflist}}

==External links==
*{{Cite EB1911 |wstitle=Incubation and Incubators |volume=14 |pages=359–369 |first=George P. |last=Mudge  |short=1}}

{{Laboratory equipment}}
{{Clinical microbiology techniques}}

[[Category:Cell biology]]
[[Category:Laboratory equipment]]
[[Category:Microbiology equipment]]
[[Category:Medical equipment]]