Fluo-4 is used to measure

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

(Ca²⁺) concentrations inside living cells, and is often used for high-throughput screening of receptor ligands and calcium permeable ion channels. The green-fluorescent calcium indicator, Fluo-4, is an improved version of the calcium indicator,

Fluo-3 Fluo-3 is a fluorescence indicator of intracellular calcium in biology, calcium (Ca2+), developed by Roger Tsien , Roger Y. Tsien and colleagues. It is used to measure Ca2+ inside living cells in flow cytometry, and confocal laser scanning micros ...

. It is commonly used as the non-fluorescent acetoxymethyl ester (Fluo-4 AM) which is cleaved inside the cell to give the free, fluorescent Fluo-4. It loads faster, is brighter at equivalent concentrations and is well-excited by the 488 nm line of the argon-ion laser which is often used in biological research laboratories. Fluo-4 and its cell-permeable AM ester are available from a few commercial vendors.

References

Biochemistry methods Cell imaging Chelating agents Fluorone dyes Fluoroarenes Acetic acids Phenol ethers Anilines {{Organic-compound-stub