A Petri dish (alternatively known as a Petri plate or cell-culture dish) is a shallow transparent lidded dish that biologists use to hold
growth medium in which
cells can be
cultured
Culture () is an umbrella term which encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups.Tylor ...
,
[R. C. Dubey (2014): ''A Textbook Of Biotechnology For Class-XI'', 4th edition, p. 469. ] originally, cells of
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
,
fungi
A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...
and small
moss
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ...
es. The container is named after its inventor, German
bacteriologist Julius Richard Petri.
It is the most common type of
culture plate. The Petri dish is one of the most common items in biology laboratories and has entered
popular culture
Popular culture (also called mass culture or pop culture) is generally recognized by members of a society as a set of practices, beliefs, artistic output (also known as, popular art or mass art) and objects that are dominant or prevalent in ...
. The term is sometimes written in lower case, especially in non-technical literature.
What was later called Petri dish was originally developed by German physician
Robert Koch in his private laboratory in 1881, as a precursor method. Petri, as assistant to Koch, at Berlin University made the final modifications in 1887 as used today.
Penicillin
Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...
, the first antibiotic, was discovered in 1929 when
Alexander Fleming noticed that
mold that had contaminated a
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
l culture in a Petri dish had killed the bacteria all around it.
Features and variants
Petri dishes are usually
cylindrical, mostly with diameters ranging from ,
[ and a height to diameter ratio ranging from 1:10 to 1:4. Squarish versions are also available.][(2019):]
Item 1219C98: Square Petri dish w/ grid
. Thomas Scientific online catalog. Accessed on 2019-10-25.[(2019):]
Product 11708573: Gosselin Square Petri Dish
. Fischer Scientific online catalog. Accessed on 2019-10-25.
Petri dishes were traditionally reusable and made of glass
Glass is a non-Crystallinity, crystalline, often transparency and translucency, transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most ...
; often of heat-resistant borosilicate glass for proper sterilization at 120–160 °C
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The d ...
.[(2019):]
Product 4909050: PYREX reusable Petri dishes: complete
. Fischer Scientific online catalog. Accessed on 2019-10-25.
Since the 1960s, plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
dishes, usually disposable, are also common.[(2019):]
Product BP94S01: Corning 100 x 15mm Polystyrene Petri Dishes
. Fischer Scientific online catalog. Accessed on 2019-10-25.
The dishes are often covered with a shallow transparent lid, resembling a slightly wider version of the dish itself. The lids of glass dishes are usually loose-fitting.[ Plastic dishes may have close-fitting covers that delay the drying of the contents.][(2019):]
Item 09-720-500: Fisherbrand disposable Petri dishes
. Fischer Scientific online catalog. Accessed on 2019-10-25. Alternatively, some glass or plastic versions may have small holes around the rim, or ribs on the underside of the cover, to allow for air flow over the culture and prevent water condensation
(99.9839 °C)
, -
, Boiling point
,
, -
, specific gas constant
, 461.5 J/( kg·K)
, -
, Heat of vaporization
, 2.27 MJ/kg
, -
, Heat capacity
, 1.864 kJ/(kg·K)
Water vapor, water vapour or aqueous vapor is the gaseous pha ...
.[(2019):]
Item SB93102: Corning 100x15mm Petri dish with three vents
. Fischer Scientific online catalog. Accessed on 2019-10-25.
Some Petri dishes, especially plastic ones, usually feature rings and/or slots on their lids and bases so that they are less prone to sliding off one another when stacked or sticking to a smooth surface by suction.[
Small dishes may have a protruding base that can be secured on a ]microscope
A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
stage for direct examination[(2019):]
Product PD1504700 MilliporeSigma PetriSlide for contamination analysis
. Fischer Scientific online catalog. Accessed on 2019-10-25.
Some versions may have grids printed on the bottom to help in measuring the density of cultures.[(2019):]
Item 41044: Petri dishes made of glass with grid and cover
. Assistent (Karl Hecht) online catalog. Accessed on 2019-10-25[
A microplate is a single container with an array of flat-bottomed cavities, each being essentially a small Petri dish. It makes it possible to inoculate and grow dozens or hundreds of independent cultures of dozens of samples at the same time. Besides being much cheaper and convenient than separate dishes, the microplate is also more amenable to automated handling and inspection.
]
History
The Petri dish was developed by German physician Julius Richard Petri (after whom the name is given) while working as an assistant to Robert Koch at Berlin University. Petri did not invent the culture dish himself; rather, it was a modified version of Koch's invention which used an agar medium that was developed by Walther Hesse. Koch had published a precursor dish in a booklet in 1881 titled "''Zur Untersuchung von Pathogenen Organismen''" (''Methods for the Study of Pathogenic Organisms''), which has been known as the "Bible of Bacteriology." He described a new bacterial culture method that used a glass slide with agar and a container (basically a Petri dish, a circular glass dish of 20 × 5 cm with matching lid) which he called ''feuchte Kammer'' ("moist chamber"). A bacterial culture was spread on the glass slide, then placed in the moist chamber with a small wet paper. Bacterial growth was easily visible.
Koch publicly demonstrated his plating method at the Seventh International Medical Congress in London in August 1881. There, Louis Pasteur exclaimed, ''"C'est un grand progrès, Monsieur''!" ("What a great progress, Sir!") It was using this method that Koch discovered important pathogens of tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...
('' Mycobacterium tuberculosis''), anthrax
Anthrax is an infection caused by the bacterium '' Bacillus anthracis''. It can occur in four forms: skin, lungs, intestinal, and injection. Symptom onset occurs between one day and more than two months after the infection is contracted. The s ...
(''Bacillus anthracis
''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus '' Bacillus''. Its infection is ...
''), and cholera ('' Vibrio cholerae''). For his research on tuberculosis, he was awarded the Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine ( sv, Nobelpriset i fysiologi eller medicin) is awarded yearly by the Nobel Assembly at the Karolinska Institute, Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or ...
in 1905. His students also made important discoveries. Friedrich Loeffler discovered the bacteria of glanders ('' Burkholderia mallei'') in 1882 and diphtheria ('' Corynebacterium diphtheriae'') in 1884; and Georg Theodor August Gaffky, the bacterium of typhoid ('' Salmonella enterica'') in 1884.
Petri made changes in how the circular dish was used. It is often asserted that Petri developed a new culture plate, but this is incorrect. Instead of using a separate glass slide or plate on which culture media were placed, Petri directly placed media into the glass dish, eliminating unnecessary steps such as transferring the culture media, using the wet paper, and reducing the chance of contamination. He published the improved method in 1887 as "''Eine kleine Modification des Koch’schen Plattenverfahrens''" ("A minor modification of the plating technique of Koch").[ Although it could have been named "Koch dish,"] the final method was given an eponymous name Petri dish.
Uses
Microbiology
Petri dishes are widely used in biology to cultivate microorganisms such as bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
, yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to consti ...
s, and molds. It is most suited for organisms that thrive on a solid or semisolid surface.
The culture medium is often an agar plate, a layer a few mm thick of agar or agarose gel containing whatever nutrients the organism requires (such as blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in th ...
, salts, carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ...
s, amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...
s) and other desired ingredients (such as dyes, indicators, and medicinal drug
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel ...
s). The agar and other ingredients are dissolved in warm water and poured into the dish and left to cool down. Once the medium solidifies, a sample of the organism is inoculated ("plated").
The dishes are then left undisturbed for hours or days while the organism grows, possibly in an incubator. They are usually covered, or placed upside-down, to lessen the risk of contamination from airborne spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...
s.
Virus
A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...
or phage cultures require that a population of bacteria be grown in the dish first, which then becomes the culture medium for the viral inoculum.
While Petri dishes are widespread in microbiological research, smaller dishes tend to be used for large-scale studies in which growing cells in Petri dishes can be relatively expensive and labor-intensive.
Contamination detection and mapping
Petri dishes can be used to visualize the location of contamination on surfaces, such as kitchen counters and utensils, clothing, food preparation equipment, or animal and human skin.[Sonja Bäumel (2009):]
Oversized petri dish
. Culture of microorganisms from the artist's skin pressed onto a body-size culture plate, photographed over the span of 44 days. Part of her ''(In)visible membrane'' project. Wageningen, Germany. Accessed on 2019-10-25.
For this application, the Petri dishes may be filled so that the culture medium protrudes slightly above the edges of the dish to make it easier to take samples on hard objects. Shallow Petri dishes prepared in this way are called Replicate Organism Detection And Counting (RODAC) plates and are available commercially.[Scott Sutton (2007): "Microbial Surface Monitoring", p. 78. Chapter 5 of Anne Marie Dixon (ed.), ''Environmental Monitoring for Cleanrooms and Controlled Environments''. ][Géraldine Daneau, Elie Nduwamahoro, Kristina Fissette, Patrick Rüdelsheim, Dick van Soolingen, Bouke C. de Jong, Leen Rigouts (2016): "Use of RODAC plates to measure containment of Mycobacterium tuberculosis in a Class IIB biosafety cabinet during routine operations." ''International Journal of Mycobacteriology'', volume 5, issue 2, pp. 148–54. ]
Cell culture
Petri dishes are also used for cell cultivation of isolated cells from eukaryotic organisms, such as in immunodiffusion studies, on solid agar or in a liquid medium.
Botany and agriculture
Petri dishes may be used to observe the early stages of plant germination
Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ...
, and to grow plants asexually from isolated cells.
Entomology
Petri dishes may be convenient enclosures to study the behavior of insects and other small animals.
Chemistry
Due to their large open surface, Petri dishes are effective containers to evaporate solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
s and dry out precipitates, either at room temperature or in ovens and desiccators.
Sample storage and display
Petri dishes also make convenient temporary storage for samples, especially liquid, granular, or powdered ones, and small objects such as insects or seeds. Their transparency and flat profile allows the contents to be inspected with the naked eye, magnifying glass, or low-power microscope without removing the lid.
In popular culture
The Petri dish is one of a small number of laboratory equipment items whose name entered popular culture. It is often used metaphorically, e.g. for a contained community that is being studied as if they were microorganisms in a biology experiment, or an environment where original ideas and enterprises may flourish.[Gary Singer (2018):]
Sonder, in the City
. Quote: ''As a native New Yorker, I tend to think of this city as a giant petri dish, in which some of the greatest breakthroughs, inventions, and audacious ideas have been nurtured to fruition.'' In Angela Dews (ed.) ''Still, in the City: Creating Peace of Mind in the Midst of Urban Chaos'', p. 40. [Isabel Slone (2018):]
What Does the Mall Goth Nostalgia Trend Really Mean?
. Quote: ''"mall goth" was a style of dress that combined the hallmarks of punk, goth and metal subcultures and thrived like bacteria in the petri dish of the early 2000s.'' Online article in the Fashion Magazine website, May 22, 2018. Accessed on 2019-10-25.
Unicode
Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...
has a Petri dish emoji
An emoji ( ; plural emoji or emojis) is a pictogram, logogram, ideogram or smiley embedded in text and used in electronic messages and web pages. The primary function of emoji is to fill in emotional cues otherwise missing from typed convers ...
, "🧫", which has the code point
In character encoding terminology, a code point, codepoint or code position is a numerical value that maps to a specific character. Code points usually represent a single grapheme—usually a letter, digit, punctuation mark, or whitespace—bu ...
U+1F9EB ( HTML entity "🧫" or "🧫", UTF-8
UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''.
UTF-8 is capable of ...
"0xF0 0x9F 0xA7 0xAB").[(2019):]
Emoji List, v12.1
. Webpage at the Unicode Consortium website. Accessed on 2019-10-25.
See also
* Microbial art
* Cell spreader
In microbiology, a cell spreader or plate spreader is a tool used to smoothly spread cells and bacteria on a culture plate, such as a petri dish.
Cell spreaders can be made from glass, plastic, or metal, and come in various shapes.
A Dri ...
* Inoculation loop
* Roux culture bottle
References
External links
{{DEFAULTSORT:Petri Dish
Laboratory glassware
Microbiology equipment
German inventions
1887 in science
1887 in Germany