Himedia Trypan blue

Trypan blue is an azo dye derived from toluidine. It is extensively used for assessment of viability of cells. It works on the principle of cell permeability dependent dye exclusion. Normal cells or those that are in the early phase of apoptosis have intact plasma membranes and thus exclude the dye whereas, dead cells or those that are in late phase of apoptosis with lysed cell membranes are permeable to the dye. Thus, viable cells appear colourless and non-viable cells appear blue. Both adherent as well as suspension cell lines can be easily stained with trypan blue and counted on hemocytometer under a light microscope.