Fluo-2 Leakage Resistant (LeakRes)

  • #0230 TEFLabs Fluo-2 LeakRes(AM) 1mg... $130 Add to Cart
  • #0232 TEFLabs Fluo-2 LeakRes(AM) 20 x 50 ug... $150 Add to Cart
  • #0234 TEFLabs Fluo-2 LeakRes(salt) 1 mg... $130 Add to Cart
  • #0236 TEFLabs Fluo-2 LeakRes(AM) 2 x 50 ug... $20 Add to Cart
  • #0238 TEFLabs Fluo-2 LeakRes(salt) 2 x 25 ug... $20 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.

Leakage resistance (LeakRes) versions have a special appendage that increases the intracellular retention – well in excess of an hour.

Compared to the corresponding non-LeakRes versions, the LeakRes indicators are identical in fluorescence prperties but are retained in the cell for hours.  In addition to Fura and Indo, TEFLabs has applied this unique technology to our new indicators Asante Calcium Red and Fluo-2.  The LeakRes indicators are available as the K+ salt and the AM forms.


Excitation:  488 nm

Emission:  515 nm

kd:  nM

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

Molecular Weight: 1113 g/mol (salt)  1317 g/mol (AM)


Typical loading protocol for Fluo-2. (The protocol for using Fluo-2 is the same that is used for Fluo-4)

  • 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 LowAFF

Fluo-2 MedAFF

Fluo-2 HighAFF

Fluo-2 NearMem

Asante Calcium Red LeakRes

Asante Calcium Green