Trypan Blue, 0.4%

Trypan Blue is an anionic dye that is not absorbed by healthy, living cells and thus does not stain them, whereas it passes through the cell membrane of dead cells and stains them blue. Cell counting, especially measuring the number of viable cells, is essential for almost all cell culture procedures and is crucial for subsequent experiments. The Trypan Blue staining method is widely used because it allows quick and simple measurement of viable cell numbers in culture media.