Cell & Organelle Stains

TMRE (Tetramethylrhodamine ethyl ester, perchlorate) and TMRM (70017) are preferred dyes for quantitative measurements of membrane potentials using the Nernst equation.

Tetrabromorhodamine 123 can be used to generate singlet oxygen (¹O₂) in mitochondrial membranes (1,2). The dye has a quantum yield for singlet oxygen generation of 0.65-0.7 and is particularly toxic to carcinoma cells.

DiOC16(3) is a green fluorescent lipophilic cyanine dye with two C16 hydrocarbon chains that can be used to stain cytoplasmic membranes.

DiB is a lipophilic cationically charged blue fluorescent dye.

Biotin-AM3-25 is a conjugate of AM3-25 and biotin. Membranes labeled with the probe can subsequently couple to avidin or streptavidin.

The fluorescence of octadecyl rhodamine B in membranes is quenched at high dye concentration but is released at dilution. This property makes the dye useful for membrane fusion assays.

NBD C6-ceramide (6-((N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl)sphingosine) has been used for following sphingolipid metabolism in cells, and as a selective stain for the Golgi apparatus in live and fixed cells.

NBD C6-sphingomyelin (6-((N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl)sphingosyl phosphocholine) has been used for following sphingolipid metabolism in cells.

The pKa of 5-carboxy-2′,7′-dichlorosulfonefluorescein is near 4 and thus the dye is potentially an excellent pH indicator for acidic organelles.

6-CFDA is membrane-permeant and thus can be loaded into cells via incubation. Once inside cells, 6-CFDA is hydrolyzed by intracellular esterases to 6-carboxyfluorescein.

5-CFDA is membrane-permeant and thus can be loaded into cells via incubation. Once inside cells, 5-CFDA is hydrolyzed by intracellular esterases to 5-carboxyfluorescein (see 50015).

This dye can be used as a low pH indicator similar to 51015, and is also useful as a general green fluorescent label.

5-(and-6)-carboxy-2′,7′-dichlorofluorescein is similar to carboxyfluorescein (51013), but has lower pK_a. It is useful for detecting pH in more acidic environment.

5-(and-6)-Carboxy-2′,7′-dichlorofluorescein diacetate is membrane-permeant and thus can be loaded into cells via incubation. The diacetate is readily hydrolyzed to 5-(and-6)-carboxy-2′,7′-dichlorofluorescein (51015) by intracellular esterases.

5-(and-6)-FAM (full name: 5-(and-6)-Carboxyfluorescein mixed isomer) has a pKa of 6.5 and can be used as a pH indicator.

A far-red cell membrane-impermeant nuclear dye with greater nuclear specificity than Draq7™. Ideal for fixed cell nuclear counterstaining with minimal cytoplasmic RNA staining.