5-Carboxynaphthofluorescein diacetate | CAS 164256-07-9

5-Carboxynaphthofluorescein diacetate is a cell-permeant, fluorescein-derived dye precursor designed for fluorescence labeling workflows where intracellular esterase activity drives conversion to a fluorescent carboxynaphthofluorescein form. Its carboxylated fluorophore enables retention after deacetylation, supporting wash-resistant imaging and staining in microscopy-based assays. The naphthofluorescein/fluorescein-like emission profile also makes it commonly used as a practical fluorescent reporter for uptake and enzymatic activation studies.

1. Live-Cell Esterase Imaging

5-Carboxynaphthofluorescein diacetate is frequently used in fluorescence microscopy to visualize intracellular esterase activity as well as dye uptake and retention. Researchers load cells with the diacetate ester, then image the resulting fluorescent product after deacetylation, enabling mapping of relative esterase-driven signal across cell populations. This format is widely adopted in chemical biology and cell biology labs for monitoring changes in intracellular processing that accompany experimental treatments, without requiring covalent labeling of biomolecules.

2. Fluorescence Microscopy Staining

5-Carboxynaphthofluorescein diacetate supports staining workflows that benefit from a membrane-permeable precursor followed by intracellular trapping of the more polar fluorescent acid. Imaging teams use it to generate bright, localized fluorescence for subcellular observation and comparative studies across experimental conditions, including time-course imaging where signal accumulation can be tracked. The carboxylate functionality of the activated dye also helps reduce signal loss during washing steps compared with non-retentive fluorophores.

3. Flow Cytometry Reporter Dye

5-Carboxynaphthofluorescein diacetate is used as a fluorescence readout in flow cytometry to quantify esterase-dependent signal at the single-cell level. Typical workflows involve incubating cells with the diacetate ester, followed by flow analysis after sufficient conversion to the fluorescent carboxynaphthofluorescein species. This application is common for generating quantitative distributions of fluorescence intensity that reflect intracellular processing capacity, enabling correlation with phenotypic changes observed under different experimental setups.

4. Enzyme-Activation Screening

5-Carboxynaphthofluorescein diacetate is also applied in small-scale fluorescence assay development where esterase-driven activation is used as a measurable response. Assay developers use the diacetate as a convenient fluorescent substrate-like reporter to monitor relative conversion kinetics in cell lysates, enzymatic preparations, or cell-based formats. The resulting fluorescence provides a straightforward signal for comparing relative activity across conditions while maintaining compatibility with standard fluorescence plate readers used in screening workflows.

5. Fluorescent Labeling Controls

5-Carboxynaphthofluorescein diacetate is commonly used as a practical control dye in experiments that involve intracellular fluorescence readouts, including studies where esterases influence signal generation. Researchers employ it to validate uptake and conversion behavior under their specific imaging or cytometry settings, helping interpret whether observed fluorescence changes arise from intracellular processing rather than from downstream labeling steps. Its activated carboxylated fluorophore supports consistent imaging after washout, making it useful for establishing baseline fluorescence behavior in method development.