AAT Bioquest Calcium Indicators

Cell-based calcium flux assays are widely used in high throughput screening (HTS) to determine agonist-stimulated and antagonist-inhibited signaling through G protein-coupled receptors (GPCRs), a large family of integral membrane proteins and an important target classs in drug discovery. Accurate measurements of intracellular calcium concentration and mobilization allows for a more comprehensive understanding of calcium regulated signaling pathways, cellular functions and pathological processees.

AAT Bioquest has developed the largest collection of calcium indicators, including Fluo-8®Cal-520®, and Calbryte™ calcium indicators, as well as, calcium flux assays to track calcium mobilization with intense fluorescent signals and in a variety of wavelength options ranging from ultraviolet to infrared.

Blue-Green Fluorescent Ca2+ Indicator

Cal-670™, AM

  • A unique violet laser-excitable fluorescent calcium indicator (Ex/Em=390/500 nm)
  • Convenient for measuring calcium response using flow cytometry

Green Fluorescent Ca2+ Indicators

Calbryte™ 520, AM

  • Exceptionally brighter than any other Ca2+ indicators under the same condition
  • Greatly improved signal to background ratio in cells
  • Significantly enhanced intracellular retention (decrease or even eliminate the use of probenecid)
  • Faster cell loading (Room temperature is OK.)

Cal-520®, AM

  • Better intracellular retention in live cells
  • Higher sensitivity, much higher signal-to-background ratio than Fluo-3, AM and Fluo-4, AM
  • Convenient, almost identical spectra to those of Fluo-4, AM

Fluo-8®, AM

  • Faster, more readily loaded into cells than Fluo-3, AM and Fluo-4, AM
  • Much brighter than Fluo-3, AM and Fluo-4, AM
  • Convenient, almost identical spectra to those of Fluo-4, AM

Red Fluorescent Ca2+ Indicators

Calbryte™ 590, AM

  • A superior replacement for Calcium Orange™ and Rhod-2
  • Ten times more sensitive than Rhod-2

Calbryte™ 630, AM

  • A superior replacement for X-Rhod-1
  • Well suited for multiplex with a green fluorescent label such as iFluor™ 488, Alexa Fluor® 488 or GFP.

NIR Fluorescent Ca2+ Indicators


  • Can be conveniently detected using Cy5® detection setup
  • Have potential for multicolor imaging


  • The only NIR Ca2+ indicator that can be potentially used for in vivo imaging