Fura-FF, AM [Fura-2FF, AM]

10x50 µg. Ex: 363 nm. Em: 512 nm. Soluble in: Water. Among the ratiometric calcium indicators, Fura-2 and Indo-1 are most commonly used. Fura-2 is excitation-ratioable while Indo-1 is emission-ratioable. Fura-2 is preferred for ratio-imaging microscopy, in which it is more practical to change excitation wavelengths than emission wavelengths. Upon binding Ca2+, Fura-2 exhibits an absorption shift that can be observed by scanning the excitation spectrum between 300 and 400 nm, while monitoring the emission at ~510 nm. The cell-permeant Fura-2FF AM is an analog of Fura-2 AM with much lower calcium binding affinity, Kd ~10 µM. This AM ester form can be loaded into live cells noninvasively.