Editing Cross-link (section)

{{Short description|Bonds linking one polymer chain to another}}
{{Hatnote|Several terms redirect here. You may be looking for [[Crosslinking of DNA]], [[London Crosslink]], or [[Infrastructure#Water management infrastructure|Water management infrastructure]]; see also [[Reticular (disambiguation)]].}}
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[[File:Vulcanization of POLYIsoprene V.2.png|thumb|[[Vulcanization]] is an example of cross-linking. Schematic presentation of two "polymer chains" (<span style="color: blue;">'''blue'''</span> and <span style="color: green;">'''green'''</span>) cross-linked after the vulcanization of natural rubber with [[sulfur]] (n = 0, 1, 2, 3, ...).]]

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|title= [[International Union of Pure and Applied Chemistry|IUPAC]] definition
|quote= A small region in a [[macromolecule]] from which at least four chains<br />emanate, and formed by reactions involving sites or groups on existing<br />macromolecules or by interactions between existing macromolecules.

''Notes''

1. The small region may be an atom, a group of atoms, or a number of<br />branch points connected by bonds, groups of atoms, or oligomeric chains.

2. In the majority of cases, a crosslink is a covalent structure but the term<br />is also used to describe sites of weaker chemical interactions, portions of<br />crystallites, and even physical interactions and entanglements.<ref>{{cite journal|title=Glossary of basic terms in polymer science (IUPAC Recommendations 1996)|journal=[[Pure and Applied Chemistry]]|year=1996|volume=68|issue=12|pages=2287–2311|quote= 1.59 Crosslink (p.2298)|doi=10.1351/pac199668122287|url=http://www.iupac.org/publications/pac/1996/pdf/6812x2287.pdf |last1= Jenkins |first1= A. D.|s2cid=98774337}}</ref>
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[[File:IUPAC definition for a crosslink in polymer chemistry.png|thumb|right|493x493px|link=https://goldbook.iupac.org/terms/view/C01409|IUPAC definition for a crosslink in polymer chemistry]]
In [[chemistry]] and [[biology]], a '''cross-link''' is a bond or a short sequence of bonds that links one [[polymer]] chain to another. These links may take the form of [[covalent bond]]s or [[ionic bond]]s and the polymers can be either synthetic polymers or natural polymers (such as [[protein]]s).

In [[polymer chemistry]] "cross-linking" usually refers to the use of cross-links to promote a change in the polymers' physical properties.

When "crosslinking" is used in the biological field, it refers to the use of a probe to link proteins together to check for [[protein–protein interaction]]s, as well as other creative cross-linking methodologies.{{Not verified in body|date=September 2018}}<!-- probe is used as a verb elsewhere in the article; but not as a noun. Could not find a source to support this statement that the term always refers to use a a probe. -->

Although the term is used to refer to the "linking of polymer chains" for both sciences, the extent of crosslinking and specificities of the crosslinking agents vary greatly.