Fura-2
Encyclopedia
Fura-2, a polyamino carboxylic acid
, is a ratiometric fluorescent dye which binds to free intracellular calcium
. It was the first widely-used dye for calcium imaging
, and remains very popular. Fura-2 is excited at 340 nm and 380 nm of light, and the ratio of the emissions at those wavelengths is directly correlated to the amount of intracellular calcium. Regardless of the presence of calcium, Fura-2 emits at 510 nm of light. The use of the ratio automatically cancels out confounding variables, such as variable dye concentration and cell thickness, making Fura-2 one of the most appreciated tools to quantify calcium levels. More recently, genetically-encoded calcium indicators based on spectral variants of the green fluorescent protein
, such as Cameleons, have supplemented the use of Fura-2 and other small molecule dyes for calcium imaging.
Polyamino carboxylic acid
thumb|left|120px|a metal complex with the [[EDTA]] anionthumb|120px|the [[glycine|glycinate]] ion can form a chelate complex with a metal ionthumb|120px| β [[alanine]]...
, is a ratiometric fluorescent dye which binds to free intracellular calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
. It was the first widely-used dye for calcium imaging
Calcium imaging
Calcium imaging is a scientific technique usually carried out in research which is designed to show the calcium status of a tissue or medium....
, and remains very popular. Fura-2 is excited at 340 nm and 380 nm of light, and the ratio of the emissions at those wavelengths is directly correlated to the amount of intracellular calcium. Regardless of the presence of calcium, Fura-2 emits at 510 nm of light. The use of the ratio automatically cancels out confounding variables, such as variable dye concentration and cell thickness, making Fura-2 one of the most appreciated tools to quantify calcium levels. More recently, genetically-encoded calcium indicators based on spectral variants of the green fluorescent protein
Green fluorescent protein
The green fluorescent protein is a protein composed of 238 amino acid residues that exhibits bright green fluorescence when exposed to blue light. Although many other marine organisms have similar green fluorescent proteins, GFP traditionally refers to the protein first isolated from the...
, such as Cameleons, have supplemented the use of Fura-2 and other small molecule dyes for calcium imaging.