Fluorescein Diacetate (syn: FDA) is an esterase substrate that can permeate cells and acts as a viability probe that measures both enzymatic activity, which is needed to activate its fluorescence, and cell-membrane integrity, which is required for intracellular retention of the fluorescent product. Upon hydrolysis by intracellular esterases, this compound yields fluorescein which is fluorescent green in color in live cells. Dead cells cannot accumulate or hydrolyse FDA thus it only stains living cells. Fluorescein diacetate can be used as a fluorogenic substrate for hGSTP1-1.
FDA can be used in diagnostic assays, manufacturing, hematology, and histology.