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==Applications==
==Applications==
The acetomethoxy derivate of calcein ('''calcein AM''') is used in biology as it can be transported through the cellular membrane into live cells, which makes it useful for testing of cell [[viability]] and for short-term labeling of cells. The acetomethoxy group obscures the part of the molecule that chelates calcium. After transport into the cell, intracellular esterases remove the group, the molecule binds to calcium within cell (resulting in strong green fluorescence), and gets trapped inside. As dead cells lack active esterases, only live cells are labeled. [http://www.howstuffworks.com/light-microscope4.htm]
The acetomethoxy derivate of calcein ('''calcein AM''') is used in biology as it can be transported through the cellular membrane into live cells, which makes it useful for testing of cell [[viability]] and for short-term labeling of cells. The acetomethoxy group obscures the part of the molecule that chelates Ca2+, Mg2+, Zn2+ and other ions. After transport into the cells, intracellular esterases remove the group, the molecule binds to Ca2+, Mg2+, Zn2+ and other ions within cell (resulting in strong green fluorescence), and gets trapped inside. As dead cells lack active esterases, only live cells are labeled. [http://www.howstuffworks.com/light-microscope4.htm]


Calcein is now rarely used as a Ca2+ or Mg2+ indicator because its fluorescence is directly sensitive to these ions only at strongly alkaline pH, and thus it is not particularly useful for measuring Ca2+ or Mg2+ in cells. Fluorescence of calcein is quenched strongly by Co2+, Ni2+ and Cu2+ and appreciably by Fe3+ and Mn2+ at physiological pH. This fluorescence quenching response can be exploited for detecting the opening of the mitochondrial permeability transition pore. Calcein is commonly used for cell tracing and in studies of endocytosis and gap junctions. [http://www.invitrogen.com/site/us/en/home/References/Molecular-Probes-The-Handbook/Indicators-for-Ca2-Mg2-Zn2-and-Other-Metal-Ions/Fluorescent-Ca2-Indicators-Excited-with-Visible-Light.html#head6]
Calcein is now rarely used as a Ca2+ or Mg2+ indicator because its fluorescence is directly sensitive to these ions only at strongly alkaline pH, and thus it is not particularly useful for measuring Ca2+ or Mg2+ in cells. Fluorescence of calcein is quenched strongly by Co2+, Ni2+ and Cu2+ and appreciably by Fe3+ and Mn2+ at physiological pH. This fluorescence quenching response can be exploited for detecting the opening of the mitochondrial permeability transition pore. Calcein is commonly used for cell tracing and in studies of endocytosis and gap junctions. [http://www.invitrogen.com/site/us/en/home/References/Molecular-Probes-The-Handbook/Indicators-for-Ca2-Mg2-Zn2-and-Other-Metal-Ions/Fluorescent-Indicators-for-Zn2-and-Other-Metal-Ions.html]


Calcein is also used to detect drug interactions with '''multidrug resistance proteins''' (ABC transporters [http://en.wikipedia.org/wiki/ATP-binding_cassette_transporter_genes]) in intact cells as it is an excellent substrate of the multidrug resistance transporter 1 (MDR1) [http://en.wikipedia.org/wiki/P-glycoprotein ] and the [http://de.wikipedia.org/wiki/Multidrug_Resistance-Related_Protein] (MRP1)<ref>Review.The role of ABC transporters in drug resistance, metabolism and toxicity. Glavinas H, Krajcsi P, Cserepes J, Sarkadi B.Curr Drug Deliv. 2004 Jan;1(1):27-42. http://www.ncbi.nlm.nih.gov/pubmed/16305368?ordinalpos=11&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum </ref>. The calcein AM assay can be used as a model for drug-drug interactions, for screening transporter substrates and/or inhibitors <ref> more detailed description of the assay/ http://www.solvo.com/pdfs/SOLVO%20Calcein%20Assay.pdf</ref>; and also to determine in vitro drug resistance of cells, including samples from patients <ref> a detailed description of the method http://www.solvo.com/pdfs/MDQ%20flyer.pdf </ref>.<ref>Calcein assay for multidrug resistance reliably predicts therapy response and survival rate in acute myeloid leukaemia.
Calcein is also used to detect drug interactions with '''multidrug resistance proteins''' (ABC transporters [http://en.wikipedia.org/wiki/ATP-binding_cassette_transporter_genes]) in intact cells as it is an excellent substrate of the multidrug resistance transporter 1 (MDR1) [http://en.wikipedia.org/wiki/P-glycoprotein ] and the [http://de.wikipedia.org/wiki/Multidrug_Resistance-Related_Protein] (MRP1)<ref>Review.The role of ABC transporters in drug resistance, metabolism and toxicity. Glavinas H, Krajcsi P, Cserepes J, Sarkadi B.Curr Drug Deliv. 2004 Jan;1(1):27-42. http://www.ncbi.nlm.nih.gov/pubmed/16305368?ordinalpos=11&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum </ref>. The calcein AM assay can be used as a model for drug-drug interactions, for screening transporter substrates and/or inhibitors <ref> more detailed description of the assay/ http://www.solvo.com/pdfs/SOLVO%20Calcein%20Assay.pdf</ref>; and also to determine in vitro drug resistance of cells, including samples from patients <ref> a detailed description of the method http://www.solvo.com/pdfs/MDQ%20flyer.pdf </ref>.<ref>Calcein assay for multidrug resistance reliably predicts therapy response and survival rate in acute myeloid leukaemia.

Revision as of 07:16, 6 March 2010

Calcein
Identifiers
3D model (JSmol)
ECHA InfoCard 100.014.507 Edit this at Wikidata
  • O=C(O5)c1ccccc1C (c3cc(CN(CC(O)=O) CC(O)=O)c(O)cc3O4) 5c2c4cc(O)c(CN(CC (O)=O)CC(O)=O)c2
Properties
C30H26N2O13
Molar mass 622.55 g/mol
Melting point Decomposes
Boiling point N/A
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Calcein, also known as fluorexon, fluorescein complex, is a fluorescent dye with an excitation and emission wavelengths of 495/515nm, respectively. Calcein also self-quenches at concentrations above 100mM. It is used as a complexometric indicator for titration of calcium ions with EDTA, and for fluorometric determination of calcium. It has the appearance of orange crystals.

Applications

The acetomethoxy derivate of calcein (calcein AM) is used in biology as it can be transported through the cellular membrane into live cells, which makes it useful for testing of cell viability and for short-term labeling of cells. The acetomethoxy group obscures the part of the molecule that chelates Ca2+, Mg2+, Zn2+ and other ions. After transport into the cells, intracellular esterases remove the group, the molecule binds to Ca2+, Mg2+, Zn2+ and other ions within cell (resulting in strong green fluorescence), and gets trapped inside. As dead cells lack active esterases, only live cells are labeled. [1]

Calcein is now rarely used as a Ca2+ or Mg2+ indicator because its fluorescence is directly sensitive to these ions only at strongly alkaline pH, and thus it is not particularly useful for measuring Ca2+ or Mg2+ in cells. Fluorescence of calcein is quenched strongly by Co2+, Ni2+ and Cu2+ and appreciably by Fe3+ and Mn2+ at physiological pH. This fluorescence quenching response can be exploited for detecting the opening of the mitochondrial permeability transition pore. Calcein is commonly used for cell tracing and in studies of endocytosis and gap junctions. [2]

Calcein is also used to detect drug interactions with multidrug resistance proteins (ABC transporters [3]) in intact cells as it is an excellent substrate of the multidrug resistance transporter 1 (MDR1) [4] and the [5] (MRP1)[1]. The calcein AM assay can be used as a model for drug-drug interactions, for screening transporter substrates and/or inhibitors [2]; and also to determine in vitro drug resistance of cells, including samples from patients [3].[4]

Calcein is also used for marking freshly hatched fish[5] and for labeling of bones in live animals.

References

  1. ^ Review.The role of ABC transporters in drug resistance, metabolism and toxicity. Glavinas H, Krajcsi P, Cserepes J, Sarkadi B.Curr Drug Deliv. 2004 Jan;1(1):27-42. http://www.ncbi.nlm.nih.gov/pubmed/16305368?ordinalpos=11&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
  2. ^ more detailed description of the assay/ http://www.solvo.com/pdfs/SOLVO%20Calcein%20Assay.pdf
  3. ^ a detailed description of the method http://www.solvo.com/pdfs/MDQ%20flyer.pdf
  4. ^ Calcein assay for multidrug resistance reliably predicts therapy response and survival rate in acute myeloid leukaemia. Karászi E, et al. Br J Haematol. 2001 Feb;112(2):308-14.
  5. ^ Marking fry using calcein - The Game Conservancy Trust
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