PhenoVue Cal-520 AM, Calcium Indicator

Calcium ions are important signaling molecules mediating a broad spectrum of intracellular, intercellular as well as extracellular functions. Ca²⁺ plays critical physiological functions such as muscle contraction, neuronal excitability, cell migration and cell growth. Intracellular Ca²⁺ is stored in the endoplasmic reticulum, sarcoplasmic reticulum, and the mitochondria. Upon cell surface receptors stimulation like GPCRs, calcium is released from these internal stores and its intracellular concentration increases from 100 nM to approximately 1 μM.

Intracellular Ca²⁺ responses have been widely investigated with fluorescent calcium probes which fluorescence signal increases upon Ca²⁺ binding.

The first-generation of fluorescent calcium indicators, including Fura-2, Fluo-3 and Rhod-2, were developed, followed by a second-generation, such as Fluo-4, with improved properties especially brightness and signal-to-noise ratio. However, the presence of anion transporters expressed at the cell surface may impair the intracellular retention of the fluorescent calcium indicators which are cleared out from cells. Inhibitors of these transporters, such as Probenecid, are commonly used but suffer from limitations such as cytotoxicity, off-targets, or inconsistent calcium flux kinetics. Such limitations can be overcome with third generation of fluorescent calcium indicators including Cal-520, Cal-590 and their corresponding Cal-520, Cal-590 Bright versions which do not require probenecid.

PhenoVue Fluorescent Calcium Indicators, encompassing Fura-2 AM, Fluo-4 AM, Cal-520 AM, Cal-590 AM, Cal-520 AM Bright and Cal-590 AM Bright, enable a myriad of applications as well as multiplexing capability to unravel intracellular calcium mediated functions.

PhenoVue Cal-520 AM is a cell permeable Ca²⁺ indicator which is metabolized by intracellular esterases and results in a negatively charged fluorescent dye. Consequently, PhenoVue Cal-520 AM exhibits higher sensitivity, significant improved signal-to-noise ratio, reduced leakage and higher intracellular retention compared to other green calcium indicators such as Fura-2 AM and Fluo-4 AM.

Typical working concentration: 5 µM

Equivalent number of microplates:

• 3-10 x 96-well microplates
• 3-10 x 384-well microplates
• 4-16 x 1536-well microplates