Fluorescein diacetate (FDA) is a cell-permeant esterase substrate that can serve as a viability probe that measures both enzymatic activity, which is require to activate its fluorescence, and cell-membrane integrity, which is required for intracellular retention of their fluorescent product.

Fluorescence-based live-dead assays can be used to evaluate the viability of mammalian cells. ... In this Application Note we present a staining protocol using fluorescein diacetate (FDA) and propidium iodide (PI), which stain viable cells and dead cells, respectively.

Dilute the fluorescein solution by add- ing enough distilled or deionized water to reach the 500-mL mark on the beaker. Stir. Note: Prepare 1% fluorescein solution by dissolving 1 g of fluorescein in 100-mL distilled water.

DIACETYL FLUORESCEIN