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Calcein, AM


Calcein AM is a cell-permeant dye that can be used to determine cell viability in most eukaryotic cells. In live cells the nonfluorescent calcein AM is converted to a green-fluorescent calcein, after acetoxymethyl ester hydrolysis by intracellular esterases. This dye is provided as 1 mg solid (C025) and 1 mg/mL solution in DMSO (C026).

Excitation/Emission: 494/515 (after cleavage)
Shipping Condition: Ice pack
Storage Conditions: -20ºC, protect from light
Molecular Formula: C45H45N2O23
Molecular Weight: 994.87
CAS Number: 148504-34-1  


To Order

Buy Cat.No. Product name Ex/Em(nm) Size Price

Calcein, AM 360/449 1 mg
500 µl




Protocol (PDF): C025  C026
COA (PDF):  C025 C026


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A precise, rapid and sensitive in vitro assay to measure the adhesion of ovarian tumour cells to peritoneal mesothelial cells.
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Clavanin permeabilizes target membranes via two distinctly different pH-dependent mechanisms.
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Frequently Asked Questions (FAQs)

I labeled my cells with Calcein, AM, but when I imaged the next day, there was no fluorescence from Calcein. Why?
Calcein, AM is a good choice for cell tracking and as a general cytoplasmic stain. However, it doesn't bind to anything and may be actively pumped out of the cells within a couple hours, which is likely what happened. The retention of Calcein within live cells is dependent upon the inherent properties of the cell type and culture conditions.
For long-term imaging, you may wish to consider a reactive cytoplasmic stain such as CFDA, SE or the CellView™ dyes.

I am doing a Live/Dead assay using Calcein, AM, for live cells and ethidium homodimer-1 for dead cells. Can I fix the cells after labeling and retain the staining?
This is not recommended. Neither Calcein nor ethidium homodimer-1 bind to any cellular components upon fixation. There is no guarantee that the dyes will be retained upon fixation or any subsequent wash steps. We recommend scoring for live and dead cells as soon as possible after staining.

I want to do a cell migration study for around 4 hours and need to fluorescently label the cells with a dye. What do you recommend?
Calcein, AM and FDA (fluorescein diaceate) are examples of some dyes used for this application. Since these dyes are not incorporated or covalently attached to any cellular components, they may have a short retention time as some cell types may actively efflux the dye out of the cells. The CellView™ dyes and CFDA, SE include either a mild thiol-reactive chloromethyl group or amine-reactive succinnimidyl ester group to allow for covalent binding to cellular components, providing for better retention.