How does trypan blue distinguish living and dead cells?

Trypan blue distinguishes between live and dead cells by using a hemocytometer and microscope. The process is this; after your sample of cells are suspended and treated with trypan blue, you then put sample onto a hemocytometer slide. Then, you must view the cells under a microscope under 10X power objective. Here, you can see which cells have been stained, and which have not. Like its name implies trypan blue stains the dead cells blue, so you can easily distinguish between live and dead cells.