Fluo-2 High Affinity (HighAff)

  • #0220 TEFLabs Fluo-2 High Aff (AM) 1mg... $110 Add to Cart
  • #0222 TEFLabs Fluo-2 High Aff (AM) 20 x 50 ug... $130 Add to Cart
  • #0224 TEFLabs Fluo-2 High Aff (salt) 1 mg... $110 Add to Cart

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Fluo-2 is one of the original Fluo series of Ca2+ indicators invented by Roger Tsien in the 1980s. Whereas Fluo-3 and Fluo-4 were commercialized, Fluo-2 was not. Subsequently, Fluo-2 has been found to be much brighter (1.5x) than Fluo-4 in cellular experiments. The increased brightness of Fluo-2 is partly attributable to its superior loading in most cell types. 

Fluo-2 HighAff has a Kd of 230 nM compared to a kd of 290 nM for Fluo-2 MediumAff.

For improved performance over Fluo indicators, TEFLabs recommends Asante Calcium Green (substantially enhanced brightness and dynamic range) and, for some applications, Asante Calcium Red (fluorescence emission at much longer wavelength).


Excitation:  488 nm

Emission:  515 nm

kd: 230 nM

Solubility: H20 (salt form)  DMSO (AM form)

Molecular Weight:  891 g/mol (salt)  1061 g/mol (AM)



The protocol for using Fluo-2 is the same that is used for Fluo-4.

Typical loading protocol for Fluo-2

  • Prepare stock solution of 1 – 10 mM Fluo-2 (AM) in DMSO
  • Dilute AM stock solution to 1 – 5 μM in aqueous medium and incubate cells for 30 – 60 minutes at room temperature. (If necessary, premix Pluronic F-127 stock solution (15% wt/vol in DMSO) with the desired volume of Fluo-2 (AM) stock solution before dispersal into aqueous medium.)
  • Wash/transfer cells into fresh medium for experimentation (for “wash-free” assays, washing may be omitted).




Fluo-2 MedAff

Fluo-2 LowAff

Fluo-2 LeakRes

Fluo-2 NearMem

Fluo-2 MAG

Asante Calcium Red (ACR)

Asante Calcium Green