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The ToxCount™ Cell Viability Assay is a simple, two-color fluorescent cell viability assay. It uses two probes, calcein AM and ethidium homodimer (EthD-1), to detect live and dead cells simultaneously. Because both dyes are non-fluorescent until interacting with cells, the background of ToxCount is very low.
This product has been discontinued.
| Name | Format | Cat No. | Price | |
|---|---|---|---|---|
| ToxCount™ | 20 x 96 rxns | 18010 | Discontinued | |
The ToxCount method
ToxCount provides two probes, calcein AM and ethidium homodimer (EthD-1), for detecting live and dead cells. Calcein AM is a non-fluorescent, cell-permeable dye that is converted to green fluorescent calcein in live cells due to acetoxymethyl ester hydrolysis by intracellular esterases. Ethidium homodimer (EthD-1) is a red fluorescent nuclear and chromosome counterstain. It does not permeate live cells, so is commonly used to detect dead cells. ToxCount data can be acquired using the IsoCyte™ laser scanner (Figure 1) from Molecular Devices (formerly BlueShift Biotechnologies) or standard fluorescence microscopes (Figure 2).
The ToxCount advantage
- Dependable, reproducible assay
- Quick and easy protocol
- Non-toxic reagents
- Economical
- High-throughput compatible
Figure 1: Analysis of ToxCount data using the IsoCyte.
The graph depicted above illustrates the mean intensity ratio for EthD-1 and calcein AM staining in each cell from two separate wells. One well was treated with saponin (copper dots) that resulted in cell death and therefore staining with EthD-1, while the second well was untreated (purple dots) resulting in calcein AM staining. Three cells in the untreated well were unhealthy and stained with EthD-1.
Figure 2: Analysis of ToxCount data using a Fluorescent Microscope.
CHO cells with calcein AM (0.5 mM) and EthD-1 (0.5 mM) imaged using the fluorescent microscope. Untreated, live cells are shown in the upper images while dead cells that had been treated with 70% methanol are shown in the bottom series of images. Microscope objective 20x; images were acquired for 1 second in the case of calcein AM and 2 seconds in the case of EthD-1.
The ToxCount™ Cell Viability Assay has been successfully used in the following publication:
- “Inhibition of Furin/Proprotein Convertase-catalysed Surface and Intracellular Processing by Small Molecules” by
Komiyama et al (2009) J. Biol. Chem. 284:15729-15738.
Contents & Storage
Lyophilized calcein AM and ethidium homodimer. Store at room temperature until reconstituted, see manual for additional details. All reagents are guaranteed stable for 6 months when stored properly.
