INDO 1 (pentasodium)

INDO 1 pentasodium is a ratiometric, free calcium ion (Ca2+) fluorescent indicator that can quantitatively monitor dynamic changes in intracellular free Ca2+ concentrations. When unbound to Ca2+ (free state), INDO 1 pentasodium exhibits a peak emission wavelength of 485 nm under UV excitation (350 nm) . Upon binding to Ca2+ (bound state), the emission peak shifts to 405 nm. INDO 1 pentasodium is highly photolabile and susceptible to photobleaching, and its emission spectrum may overlap with the autofluorescence of NADH[1].