Quest Fluo-8L(TM), potassium salt

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. Quest Fluo-8(TM) are developed to improve cell loading and calcium response while maintaining the convenient Fluo-3 and Fluo-4 spectral wavelength of maximum excitation at approx. 490 nm and maximum emission at approx. 520 nm. Quest Fluo-8(TM) AM only requires room temperature while Fluo-3 AM and Fluo-4 AM require 37 °C cell loading. In addition, Quest Fluo-8(TM) is 2 times brighter than Fluo-4 AM, and 4 times brighter than Fluo-3 AM. ABD Bioquest offers a set of our outstanding Quest Fluo-8(TM) reagents with different calcium binding affinities (Quest Fluo-8: Kd = 389 nM, Quest Fluo-8H: Kd = 232 nM, Quest Fluo-8L: Kd = 1.86 µM). We also offer versatile packing sizes to meet your special needs, e.g., 1 mg, 10x50 µg, 20x50 µg, HTS packages with no additional packaging charge.