Fixable viability dyes
VivaFix™ Cell Viability Assays allow accurate discrimination between live and dead cells in fixed or unfixed samples in Flow Cytometry, Cell Sorting and Microscopy.
In Flow Cytometry experiments the exclusion of dead cells in a sample is an important step to prevent errors in data interpretation due to non-specific fluorescence signals. In Microscopy cell viability and live:dead cell ratios are parameters that are frequently used to determine cell health.
VivaFix Cell Viability Dyes covalently bind to free primary amines which in live cells are present on the cell surface. Where the membrane is compromised, the dyes permeate the cells and react with intracellular primary amines. There is greater fluorescence due to increased content of accessible free amines in dead cells allowing them to be easily distinguished from live cells (Figure 1). In addition, they are available in a range of excitation and emission spectra for convenient addition to multi-color flow cytometry panels.
Figure 1. VivaFix Cell Viability Assay chemistry. A, live cell with VivaFix Dye bound to surface primary amines. B, dead cell with VivaFix Dye bound to surface and intracellular primary amines.
Excitation Max, nm
Emission Max, nm
Optimal excitation laser
We also offer non membrane permeable DNA-binding cell staining dyes excited by the 488 nm and 561 nm laser to allow you to assess the viability of your cells:
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