Fura-4F Pentapotassium salt | CAS 299172-08-0

Fura-4F Pentapotassium salt is a high-affinity, cell-imaging compatible fluorescent Ca2+ indicator built around a BAPTA-derived fluorophore scaffold. As a pentapotassium salt, it is designed to provide efficient aqueous handling and strong fluorescence response upon Ca2+ binding, making it widely used in fluorescence microscopy and quantitative fluorescence readouts of intracellular calcium dynamics. Its ratiometric behavior supports Ca2+-dependent signal tracking in experimental systems where temporal changes in calcium concentration are the primary measurement.

1. Intracellular Calcium Imaging

Fura-4F Pentapotassium salt is used by cell biology and neuroscience research groups to visualize and quantify intracellular Ca2+ transients in cultured cells. Investigators commonly load the indicator into cells and monitor Ca2+-dependent fluorescence changes during stimulation protocols, enabling time-resolved mapping of calcium signaling dynamics in response to neurotransmitter agonists, receptor activation, or electrical perturbations. The pentapotassium salt form supports practical preparation of Ca2+ imaging solutions and helps deliver reproducible fluorescence behavior in microscopy workflows.

2. Calcium Kinetics In Fluorescence Assays

Fura-4F Pentapotassium salt is frequently employed in fluorescence-based assay development to measure Ca2+-dependent kinetics in suspensions, lysates, or reconstituted biochemical systems. Assay developers use the indicator as a quantitative readout for Ca2+ uptake, release, buffering capacity, or enzyme-linked Ca2+ flux, often coupling it to plate readers or cuvette fluorometers for real-time monitoring. This application is especially common when the experimental goal is to generate concentration-time profiles of Ca2+ without relying on Ca2+-specific electrodes.

3. Flow Cytometry Calcium Readouts

Fura-4F Pentapotassium salt is used in flow cytometry workflows where Ca2+ levels are assessed across large cell populations under defined stimulation conditions. Researchers load cells with the indicator and then measure Ca2+-dependent fluorescence shifts to generate distributions reflecting basal Ca2+ and stimulus-evoked calcium responses. This approach supports comparative analysis of calcium signaling variability between experimental groups, including studies of receptor signaling strength, ion channel function, and assay optimization for high-throughput screening of calcium-modulating conditions.

4. Calcium Calibration And Standardization

Fura-4F Pentapotassium salt is also used as a reference Ca2+ indicator in calibration and standardization experiments that establish fluorescence-to-Ca2+ conversion in a given instrument and buffer environment. Researchers prepare Ca2+ calibration series to relate measured fluorescence ratios to known Ca2+ concentrations, improving the interpretability of quantitative imaging and kinetic assays. In practice, this application helps ensure that reported Ca2+ dynamics reflect experimentally relevant concentration ranges rather than instrument-specific fluorescence scaling.