fura-2

Fura-2 potassium salt is a commonly used UV-excitable fluorescent probe for intracellular calcium ion imaging.

Fura-2 is a ratiometric fluorescent calcium indicator that can be used to detect calcium in cells. It is a pentacarboxylate that displays excitation maxima of 340 and 380 nm at high and low calcium concentrations, respectively, when the emission is fixed at 510 nm, enabling determination of ratiometric measurements of calcium influx in live cells.

Fura-2 AM is a membrane-permeable Ca²⁺ (calcium ion) indicator that is converted to Fura-2 by esterase within cells. Its fluorescence emission wavelength is around 510 nm, with excitation maxima at 340 nm under high calcium concentrations and 380 nm under low calcium concentrations. Calcium ion concentrations can be calculated using the fluorescence intensity ratio.

Fura-2 pentasodium is a ratiometric fluorescent dye utilized for intracellular calcium ion imaging, with a Kd value of 140 nM. Its emission wavelength is 510 nm, and it features excitation wavelengths of 340 nm and 380 nm. The fluorescence intensity ratio of 340/380 is directly proportional to the intracellular Ca2+ (calcium ion) levels.

Mag-Fura-2 AM, a cell-permeable fluorescent compound, serves as a selective indicator for magnesium ions (Mg2+), demonstrating significant preference for Mg2+ over other bivalent ions including zinc (Zn2+), copper (Cu2+), and calcium (Ca2+). It notably exhibits over 13,000-fold greater selectivity for Mg2+ compared to Ca2+ (Mg2+Kd = 1.9 nM vs. Ca2+Kd = 25 μM). The excitation and emission peak wavelengths are 369 nm and 511 nm, respectively. Further, Mag-Fura-2 AM is utilized as an indirect measure of ATP consumption or production due to its magnesium ion sensitivity.

Mag-Fura-2 tetrapotassium, a UV-excitable fluorescent Mg²⁺ Ca²⁺ indicator (Ex=334-360 nm, Em=510 nm), is used to determine Mg²⁺ and Ca²⁺ concentrations [1] [2].

Rhod-2 (potassium salt) is a water-soluble, red fluorescent calcium indicator that exhibits a significant shift in fluorescence intensity upon calcium binding (ex max = 549 nm; calcium-free v. ex em max = 552 581 nm; calcium-bound). Unlike the UV-excitable indicators fura-2 and indo-1, it does not demonstrate a spectral shift.

Rhod-2 (sodium salt) is a water-soluble, red fluorescent calcium indicator. It exhibits a significant shift in fluorescence intensity upon calcium binding (ex max = 549 nm; calcium-free v. ex em max = 552 581 nm; calcium-bound). [1][2] Unlike the UV-excitable indicators fura-2 and indo-1 , there is no accompanying spectral shift.

Fura-FF AM is a cell-permeable acetoxymethyl ester of the fluorescence calcium indicator fura-FF (potassium salt). Upon entering cells, it is hydrolyzed by intracellular esterases to produce fura-FF, a difluorinated derivative of the calcium indicator fura-2. Unlike fura-2, fura-FF has negligible magnesium sensitivity, reducing interference from this cation, and a higher calcium dissociation constant (Kd(calcium) = 6 μM for fura-FF and 0.14 μM for fura-2). The spectral properties of fura-FF are similar to those of fura-2, with fura-FF displaying excitation emission spectra of 365 514 nm in the absence of calcium and shifting to 339 507 nm in the presence of high calcium concentrations. Low affinity calcium dyes, including fura-FF, are preferred for studying compartments with high calcium concentrations, such as mitochondria, or in cell systems with relatively low calcium buffering capacities, such as neuronal dendrites and spines.

Fura PE-3 potassium, a Ca 2+ sensitive fluorophore, is utilized for loading in IPA (intrapulmonary arteries) and MA (mesenteric resistance arteries) in vasoconstriction research [1] [2].

Fura Red AM, a fluorescent probe, is utilized for visualizing cytosolic [Ca(2+)] distribution in living plant tissue under an excitation wavelength of 488 nm [1].