In vitro

In vitro

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Encyclopedia
In vitro refers to studies in experimental biology that are conducted using components of an organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

 that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments are commonly referred to as "test tube experiments". In contrast, the term in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...

refers to work that is conducted with living organisms in their normal, intact state, while ex vivo
Ex vivo
Ex vivo means that which takes place outside an organism. In science, ex vivo refers to experimentation or measurements done in or on tissue in an artificial environment outside the organism with the minimum alteration of natural conditions...

refers to studies on functional organs that have been removed from the intact organism.

Common examples of in vitro experiments include (a) cells derived from multicellular organisms (cell culture
Cell culture
Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...

 or tissue culture
Tissue culture
Tissue culture is the growth of tissues or cells separate from the organism. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar...

), (b) subcellular components (e.g. mitochondria or ribosomes), (c) Cellular or subcellular extracts (e.g. wheat germ or reticulocyte
Reticulocyte
Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body.Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. Like mature red blood cells,...

 extracts), or (d) purified molecules in the test tube (often proteins, DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

, or RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

, either individually or in combination).

Advantages of in vitro studies


Living organisms are extremely complex functional systems that are made up of, at a minimum, many tens of thousands of genes, protein molecules, RNA molecules, small organic compounds, inorganic ions and complexes in an environment that is spatially organized by membranes and, in the case of multicellular organisms, organ systems. For a biological organism to survive, these myriad components must interact with each other and with their environment in a way that processes food, removes waste, moves components to the correct location, and is responsive to signalling molecules, other organisms, light, sound, temperature and many other factors.

This extraordinary complexity of living organisms is a great barrier to the identification of individual components and the exploration of their basic biological functions. The primary advantage of in vitro work is that it permits an enormous level of simplification of the system under study, so that the investigator can focus on a small number of components. For example, the identity of proteins of the immune system (e.g. antibodies), and the mechanism by which they recognize and bind to foreign antigens would remain very obscure if not for the extensive use of in vitro work to isolate the proteins, identify the cells and genes that produce them, study the physical properties of their interaction with antigens, and identify how those interactions lead to cellular signals that activate other components of the immune system.

Disadvantages of in vitro studies


The primary disadvantage of in vitro experimental studies is that it can sometimes be very challenging to extrapolate from the results of in vitro work back to the biology of the intact organism. Investigators doing in vitro work must be careful to avoid over-interpretation of their results, which can sometimes lead to erroneous conclusions about organismal and systems biology.

For example, scientists developing a new viral drug to treat an infection with a pathogenic virus (e.g. HIV-1) may find that a candidate drug functions to prevent viral replication in an in vitro setting (typically cell culture). However, before this drug is used in the clinic, it must progress through a series of in vivo trials to determine if it is safe and effective in intact organisms (typically small animals, primates and humans in succession). Typically, many candidate drugs that are effective in vitro prove to be ineffective in vivo because of issues associated with delivery of the drug to the affected tissues, or toxicity towards essential parts of the organism that were not represented in the initial in vitro studies.

Examples of in vitro work


Polymerase chain reaction
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

is a method for selective replication of specific DNA and RNA sequences in the test tube.

Protein purification
Protein purification
Protein purification is a series of processes intended to isolate a single type of protein from a complex mixture. Protein purification is vital for the characterization of the function, structure and interactions of the protein of interest. The starting material is usually a biological tissue or...

involves the isolation of a specific protein of interest from a complex mixture of proteins, often obtained from homogenized cells or tissues.

In vitro fertilization is used to allow spermatozoa to fertilize eggs in a culture dish before implanting the resulting embryo or embryos into the uterus of the prospective mother.

In vitro diagnostics
In vitro diagnostics
In vitro diagnostic tests are medical devices intended to perform diagnoses from assays in a test tube, or more generally in a controlled environment outside a living organism...

refers to a wide range of medical and veterinary laboratory tests that are used to diagnose diseases and monitor the clinical status of patients using samples of blood, cells or other tissues obtained from a patient.

See also


  • Animal testing
    Animal testing
    Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million...

  • Ex vivo
    Ex vivo
    Ex vivo means that which takes place outside an organism. In science, ex vivo refers to experimentation or measurements done in or on tissue in an artificial environment outside the organism with the minimum alteration of natural conditions...

  • In situ
    In situ
    In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...

  • In utero
    In utero
    In utero is a Latin term literally meaning "in the womb". In biology, the phrase describes the state of an embryo or fetus. In legal contexts, the phrase is used to refer to unborn children. Under common law, unborn children are still considered to exist for property transfer purposes.-See also:*...

  • In vivo
    In vivo
    In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...

  • In silico
    In silico
    In silico is an expression used to mean "performed on computer or via computer simulation." The phrase was coined in 1989 as an analogy to the Latin phrases in vivo and in vitro which are commonly used in biology and refer to experiments done in living organisms and outside of living organisms,...

  • In papyro
    In papyro
    in papyro: referring to experiments or studies carried out only on paper. For example, the term may be applied to epidemiological studies that do not involve clinical subjects, such as meta-analysis. The term is similar to phrases such as in vivo, in vitro, or in silico...

  • In natura
    In natura
    In natura is a phrase to describe conditions present in a non-laboratory environment, to differentiate it from in vivo and ex vivo conditions., -See also:*in vitro*in silico*ex vivo*in situ*in utero*in papyro*in planta...

  • In vitro fertilization
  • In Vitro Cellular & Developmental Biology - Animal
    In Vitro Cellular & Developmental Biology - Animal
    In Vitro Cellular & Developmental Biology – Animal is a scientific journal devoted to in vitro biology in animals. Its plant counterpart is In Vitro Cellular & Developmental Biology – Plant.- Subjects covered :...

  • In Vitro Cellular & Developmental Biology - Plant
    In Vitro Cellular & Developmental Biology - Plant
    In Vitro Cellular & Developmental Biology - Plant is a scientific journal devoted to in vitro biology in plants. Its original research and reviews cover developments and research in plant cell and tissue culture and biotechnology from around the world...

  • Slice preparation
    Slice preparation
    The slice preparation or brain slice is a laboratory technique in electrophysiology that allows the study of a synapse or neural circuit in isolation from the rest of the brain, in controlled physiological conditions. It involves stimulating and/or recording from a slice of brain tissue immersed in...