Calcein

Chembox new
Name = Calcein
ImageFile = Calcein.svg
ImageName =
IUPACName =
Section1 = Chembox Identifiers
CASNo = 1461-15-0
SMILES = 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
Section2 = Chembox Properties
Formula = C₃₀H₂₆N₂O₁₃
MolarMass = 622.55 g/mol
Density =
MeltingPt = Decomposes
BoilingPt = N/A

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 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]

Calcein is also used for marking freshly hatched fish [ [http://www.gct.org.uk/text03.asp?PageId=331 Marking fry using calcein - The Game Conservancy Trust ] ] and for labeling of bones in live animals.

References