Fura Red, AM | CAS 149732-62-7

Fura Red, AM is a cell-permeant acetoxymethyl (AM) ester form of the ratiometric calcium indicator Fura Red, designed for intracellular Ca2+ fluorescence imaging. After esterase-mediated de-esterification inside cells, it provides Ca2+-dependent fluorescence suitable for monitoring dynamic calcium signals with microscopy and plate-based fluorescence readouts. Its AM ester format supports common workflows in live-cell calcium assays where loading efficiency and cytosolic access are critical.

1. Live-Cell Calcium Imaging

Fura Red, AM is used by cell biology and neuroscience research groups to visualize intracellular Ca2+ transients in adherent or suspension cultures. Following AM loading, the probe reports calcium-dependent fluorescence changes that can be tracked over time to monitor stimulus-evoked signaling, oscillatory Ca2+ behavior, and spatiotemporal propagation patterns. Researchers typically employ fluorescence microscopy setups with appropriate excitation/emission filters to capture ratiometric readouts that help account for focus drift and probe distribution during time-lapse experiments.

2. Plate-Based Calcium Assays

Fura Red, AM is frequently implemented in fluorescence microplate workflows for screening and assay development focused on calcium signaling modulation in cultured cells. After loading, the Ca2+-responsive signal is read on standard fluorescence plate readers, enabling kinetic measurements across many wells and conditions. This format is commonly used when researchers need robust, time-resolved Ca2+ response curves for comparing relative changes in intracellular calcium under different treatments, stimulation protocols, or genetic perturbations.

3. Flow Cytometry Calcium Readout

Fura Red, AM is applied in flow cytometry to quantify intracellular Ca2+ levels across large cell populations after loading and stimulation. In these workflows, cells are stained with the AM ester, allowed to de-esterify, and then analyzed for calcium-dependent fluorescence intensity or ratiometric signal using instrument-specific channels. This approach supports population-level assessment of Ca2+ response heterogeneity, including shifts in baseline calcium and stimulus-induced changes in fluorescence distribution.

4. Calcium Signaling Kinetics

Fura Red, AM supports real-time monitoring of calcium dynamics in experiments requiring controlled timing between stimulation and optical acquisition. Researchers use it to capture rapid rises and decays of intracellular Ca2+ associated with receptor activation, ion channel activity, or intracellular signaling cascades, where temporal resolution is important for interpreting event sequences. The ratiometric nature of the de-esterified indicator format is leveraged to improve robustness of kinetic traces against variations in dye loading and imaging conditions.