The intercellular calcium flux assay is widely used for monitoring GPCRs and calcium channels. In our previous work,
Cal-520® AM has been developed as a new green fluorescent dye with a significantly improved signal to noise ratio and better intracellular retention than
Fluo-3 AM and
Fluo-4 AM. In this study, two new red fluorescent calcium indicators,
Cal-590 AM and
Cal-630AM, have been developed for monitoring calcium ions in GFP cell lines or multiplexed with green-fluorescent dyes. Cal-590 AM and Cal-630AM are much more sensitive than rhodamine calcium dyes (such as
Rhod-2, AM). Instead of located mostly in mitochondria as for
Rhod-2, Cal-590 and Cal-630 are retained in cytoplasm. When stimulated with bioactive compounds, the red fluorescence of Cal-590 and Cal-630 are greatly enhanced when binding intracellular calcium with no overlap with green fluorescence.
Cal 520 AM, Cal-590AM and Cal-630 AM have been developed for evaluating GPCR and calcium channel targets, as well as for screening their agonists and antagonists. They have the following features: