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Fluorescence

ToxCount™ Cell Viability Assay

convenient, accurate cell viability assay

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.

 
Name Format Cat No. Price  
ToxCount™ 20 x 96 rxns 18010 $340 Buy Now

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.

 

ToxCount data

 
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:

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.