CAS No.: 596-09-8
Molecular Formula: C24H16O7
Molecular Weight: 416.38
EINECS No.: 209-877-6 

Fluorescein diacetate (FDA) is an important fluorescent probe, and its core applications can be summarized as follows: 

1.Cell viability assay
As an esterase substrate, FDA can penetrate the cell membrane of living cells and be hydrolyzed by intracellular esterase into fluorescein, emitting green fluorescence (Ex/Em ≈ 494/521 nm). Dead cells, due to the disruption of membrane integrity or loss of enzyme activity, cannot accumulate fluorescence signals, thus enabling efficient discrimination between living and dead cells. 

2. Enzyme Activity Analysis
Esterase Activity Assay: FDA hydrolysis depends on esterase activity, and its fluorescence intensity is positively correlated with enzyme activity, which is suitable for drug screening or pathological research.
Glutathione S-Transferase (GSTP1-1) Research: FDA can be used as a specific fluorescent substrate for hGSTP1-1 to quantitatively determine enzyme activity and screen inhibitors. 

3. Cell Metabolism and Dynamic Tracking
Migration and Proliferation Monitoring: Labeled living cells (such as T cells or tumor cells) can be tracked for their migration paths or proliferation status through long-lasting fluorescence signals.
Drug Metabolism Research: After labeling drug carriers, their release and metabolism processes within cells can be observed through fluorescence changes. 

4. Flow Cytometry and Histochemistry
FDA is applicable to cell sorting in flow cytometers and can also be used for fluorescence staining of esterase activity in tissue sections.