INDO 1 pentasodium

INDO 1 pentasodium functions as a ratiometric, free calcium ion (Ca2+) fluorescent indicator, capable of quantitatively tracking the dynamic changes in intracellular free Ca2+ concentration. In its free state, when unbound to Ca2+, INDO 1 pentasodium emits light at a peak of 485 nm upon excitation by ultraviolet light at 350 nm. When bound to Ca2+, the emission peak shifts to 405 nm. INDO 1 pentasodium exhibits considerable photoinstability, being prone to photobleaching, and its emission spectrum may overlap with the autofluorescence of NADH.