# Fluo-3

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Fluo-3
> Markdown URL: https://mediated.wiki/source/Fluo-3.md
> Source: https://en.wikipedia.org/wiki/Fluo-3
> Source revision: 1324045087
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{{Chembox
| ImageFile = Fluo-3.svg
| ImageSize = 200px
| PIN = 2,2′-<nowiki/>{[2-(2-<nowiki/>{2-[Bis(carboxymethyl)amino]-5-(2,7-dichloro-6-hydroxy-3-oxo-3''H''-xanthen-9-yl)phenoxy}ethoxy)-4-methylphenyl]azanediyl}diacetic acid
| OtherNames = 
|Section1={{Chembox Identifiers
| CASNo = 123632-39-3
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 23D4W0B50Y
| PubChem = 104978
| ChemSpiderID = 94730
| ChEMBL = 509919
| SMILES = O=C(O)CN(c5ccc(cc5OCCOc4c(N(CC(=O)O)CC(=O)O)ccc(C=1c3c(OC=2C=1\C=C(\Cl)C(=O)C=2)cc(O)c(Cl)c3)c4)C)CC(=O)O
| InChI = 1/C36H30Cl2N2O13/c1-18-2-4-24(39(14-32(43)44)15-33(45)46)30(8-18)51-6-7-52-31-9-19(3-5-25(31)40(16-34(47)48)17-35(49)50)36-20-10-22(37)26(41)12-28(20)53-29-13-27(42)23(38)11-21(29)36/h2-5,8-13,41H,6-7,14-17H2,1H3,(H,43,44)(H,45,46)(H,47,48)(H,49,50)
| InChIKey = OZLGRUXZXMRXGP-UHFFFAOYAI
| StdInChI = 1S/C36H30Cl2N2O13/c1-18-2-4-24(39(14-32(43)44)15-33(45)46)30(8-18)51-6-7-52-31-9-19(3-5-25(31)40(16-34(47)48)17-35(49)50)36-20-10-22(37)26(41)12-28(20)53-29-13-27(42)23(38)11-21(29)36/h2-5,8-13,41H,6-7,14-17H2,1H3,(H,43,44)(H,45,46)(H,47,48)(H,49,50)
| StdInChIKey = OZLGRUXZXMRXGP-UHFFFAOYSA-N
  }}
|Section2={{Chembox Properties
| C=36 | H=30 | Cl=2 | N=2 | O=13
| Appearance = 
| Density = 
| MeltingPt = 
| BoilingPt = 
| Solubility =
  }}
|Section3={{Chembox Hazards
| MainHazards = 
| FlashPt = 
| AutoignitionPt =
  }}
}}

'''Fluo-3''' is a [fluorescence](/source/fluorescence) indicator of intracellular [calcium](/source/calcium_in_biology) (Ca<sup>2+</sup>), developed by [Roger Y. Tsien](/source/Roger_Tsien).<ref>{{cite journal | last1 = Tsien | first1 = R.Y. | year = 1980 | title = New calcium indicators and buffers with high selectivity against magnesium and protons: design, synthesis, and properties of prototype structures | journal = Biochemistry | volume = 19 | issue = 11 | pages = 2396–2404 | doi = 10.1021/bi00552a018| pmid = 6770893 }}</ref> It is used to measure Ca<sup>2+</sup> inside living cells in [flow cytometry](/source/flow_cytometry), and [confocal laser scanning microscopy](/source/confocal_laser_scanning_microscopy) using visible light excitation (compatible with [argon laser](/source/argon_laser) sources operating at 488&nbsp;nm). Fluo-3 and derivatives ([Fluo-4](/source/Fluo-4), Fluo-5 etc) have also been widely used with [two-photon excitation microscopy](/source/two-photon_excitation_microscopy). Fluo-3 is an essentially nonfluorescent compound, but upon binding of Ca<sup>2+</sup> its fluorescence increases sharply with an emission maximum at 525&nbsp;nm suitable for conventionally used detectors designed for [fluorescein isothiocyanate](/source/fluorescein_isothiocyanate) (FITC) measurements. This large change in fluorescence coupled with a good yield of photons provides very high contrast which allowed the detection of microscopic Ca<sup>2+</sup> release events inside cells called "[Calcium sparks](/source/Calcium_sparks)".<ref>{{cite journal | last1 = Cheng | first1 = H. | last2 = Lederer | first2 = W.J. | last3 = Cannell | first3 = M.B. | year = 1993 | title = Calcium Sparks - Elementary Events Underlying Excitation-Contraction Coupling in Heart-Muscle | journal = Science | volume = 262 | issue = 5134| pages = 740–744 | pmid = 8235594 | doi=10.1126/science.8235594| bibcode = 1993Sci...262..740C }}</ref> Whereas the salts of fluo-3 are unable to penetrate cells, loading can be achieved using its acetoxymethyl (AM) [ester](/source/ester) derivative. Once inside the cell, unspecific [esterase](/source/esterase)s cleave the ester effectively trapping fluo-3.<ref>Haugland, RP. ''Handbook of Fluorescent Probes and Research Products''. Molecular Probes, 2010</ref>

As calcium is a key [second messenger](/source/second_messenger) within cells, the specific properties of fluo-3 enable researchers to investigate the time-resolved dynamics of intracellular [signal transduction](/source/signal_transduction) in a diverse range of cells.<ref>Gamsjäger, T. ''Flow Cytometry of Intracellular Calcium in Platelets''. Grin, 2012</ref><ref>Lambert, DG. ''Calcium Signaling Protocols''. Humana Press, 2006</ref>

==References==
{{Reflist}}

Category:9-phenylfluorone dyes
Category:Cell imaging
Category:Acetic acids
Category:Anilines
Category:Phenol ethers
Category:Chloroarenes
Category:Phenylogous carboxylic acids
Category:Xanthenes
Category:Glycol ethers

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Adapted from the Wikipedia article [Fluo-3](https://en.wikipedia.org/wiki/Fluo-3) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Fluo-3?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.