The Default Single-Wavelength Calcium Indicator

August 19, 2026

BlueskyReddit
Houston Methodist

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Quality of Results

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Company:

Invitrogen

Product Name:

Fluo-4, AM, cell permeant

Catalog Number:

F14201

We measure intracellular calcium flux as the functional readout for receptor and mechanosensitive channel activation in primary immune cells.

Experimental Design and Results Summary

Application

Live Cell Imaging / Flow Cytometry

Starting Material

Primary human and mouse immune cells

Tips

A stock that has been thawed a dozen times loads worse and less reproducibly than a fresh one.

Results Summary

The fluorescence increase on calcium binding is large, the excitation sits exactly on the 488 nm line every instrument has, and the response is fast enough to capture the initial transient rather than just the plateau. Loading was straightforward at low micromolar concentrations with Pluronic, and cells tolerated it well over our acquisition windows.

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Summary

The Good

Large fluorescence change on calcium binding, 488 nm excitation works on every instrument, fast kinetics, and single-use vials eliminate freeze-thaw degradation.

The Bad

: Single-wavelength, so no ratiometric correction for loading differences and no absolute calcium quantification; AM ester chemistry is unforgiving of wet DMSO.

The Bottom Line

The reagent to reach for first for calcium flux. Buy the special packaging rather than the bulk vial, the reproducibility gain is worth more than the price difference.

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