– Membrane-permeant AM ester form of Fluo-4 that can enter into into cells via incubation. Fluo-4 AM ester itself does not bind Ca² , but it is readily hydrolyzed to Fluo-4 by endogenous esterases once the dye is inside the cells. Fluo-4 AM ester is often used to measure intracellular calcium in high throughput drug screening.    Fluo-4 is an analog of Fluo-3 with the two chlorine substituents replaced by fluorines, which results in increased fluorescence excitation at 488 nm that gives higher fluorescence signal. Fluo-4 has its absorption maximum at 494 nm, thus making it excitable by the argon-ion laser. Fluo-4 is essentially nonfluorescent without Ca² present, but the fluorescence increases at least 100 times on Ca² binding. Also, because Fluo-4 binds Ca² more weakly (higher Kd) than do fura-2 and indo-1, it is more useful for measuring high transient Ca² concentration during Ca² spikes.    Fluo-4 AM ester can be used to detect intracellular free calcium by fluorescence microscopy, flow cytometry, or fluorescence microplate reader.    We also sell Fluo-4 as a membrane-impermeant pentapotassium salt version. 

 
• Orange red solid soluble in DMSO
 
• Store -20°C and protect from light, especially when in solution
 
• Ex/Em of Ca² €“bound form: 494/506 nm
 
• K_d for Ca²  in buffer: ~335 nM
 
• C₅₁H₅₀F₂N₂O₂₃
 
• MW: 1096.95
 
• [273221-67-3]
 

Handling

Store with desiccant; Protect from light