Fluo-8®, the Brightest Green Ca2+ Indicators

Calcium measurement is critical for numerous biological investigations. Fluorescent probes that show spectral responses upon binding Ca2+ have enabled researchers to investigate changes in intracellular free Ca2+ concentrations by using fluorescence microscopy, flow cytometry, fluorescence spectroscopy and fluorescence microplate readers. Fluo-3 and Fluo-4 are most commonly used among the visible light-excitable calcium indicators. However, Fluo-3 AM and Fluo-4 AM are only moderately fluorescent in live cells upon esterase hydrolysis, and require harsh cell loading conditions to maximize their cellular calcium responses.

Fluo-8^® has been developed to improve cell loading and calcium response while maintaining the convenient Fluo-3 and Fluo-4 spectral wavelength of maximum excitation @ ~490 nm and maximum emission @ ~520 nm. Fluo-8^® AM only requires room temperature while Fluo-3 AM and Fluo-4 AM require 37°C cell loading. In addition, Fluo-8^® is 2 times brighter than Fluo-4 AM, and 4 times brighter than Fluo-3 AM.

AAT Bioquest offers a set of our outstanding Fluo-8^® reagents with different calcium binding affinities (Fluo-8^®: K_d = 389 nM; Fluo-8H™: K_d = 232 nM; Fluo-8L™: K_d = 1.86 µM; Fluo-8FF™: K_d = 10 µM). We also offer versatile packing sizes to meet your special needs, e.g., 1 mg, 10x50 µg or 20x50 µg.