Better Intracellular Retention

Cal-520™, Green Fluorescent Calcium Dyes

Cal-520™ provides the most robust homogeneous fluorescence-based assay tool for detecting intracellular calcium mobilisation. Cal-520™ AM is a new fluorogenic calcium-sensitive dye with a significantly improved signal to background ratio and intracellular

retention compared to the existing green calcium indicators (such as Fluo-3 AM and Fluo-4 AM). The higher signal/background ratio and better intracellular retention make the Cal-520™ calcium assay a robust tool for evaluating GPCR and calcium channel targets as well as for screening their agonists and antagonists.

fig-2-cal-520AAT Bioquest’s preliminary in-house research indicated that Cal-520™ AM can be readily loaded to a guinea pig heart and stays there for a few hours in the absence of probenecid. The calcium signal can be readily monitored using Cal-520™ AM while it is difficult to observe the calcium signal under the same conditions using other green calcium dyes such as Fluo-3 AM and Fluo-4 AM.

Key Features

  • Better Intracellular Retention, Cal-520™ AM is well retained in live cells.
  • Higher Sensitivity, Cal-520™ AM has the highest signal/background ratio.
  • Convenient, Cal-520™ AM has almost identical spectra to those of Fluo-4 AM.



  • Cat. No. 21131 Cal-520™ AM
  • Cat. No. 21141 Cal-520™, potassium salt
  • Cat. No. 21136 Cal-520™, sodium salt
  • Cat. No. 21142 Cal-520FF™ AM
  • Cat. No. 21144 Cal-520FF™, potassium salt
  • Cat. No. 20501 Cal Green™-1 (equivalent to Calcium Green™-1 AM)
  • Cat. No. 20500 Cal Green™-1, hexapotassium salt (equivalent to Calcium Green™-1)


outstanding technical support


we offer a full product guarantee


we offer free delivery to UK universities and non profit organisations