Trypan Blue Exclusion is a vital technique used in cell biology to assess cell viability. In this method, Trypan Blue, a blue dye, is added to a cell suspension. Live cells, which have intact membranes, do not take up the dye and remain clear, while dead cells absorb the dye and appear blue. This allows researchers to distinguish between viable and non-viable cells under a microscope. The process is straightforward: a small sample of cells is mixed with the dye, and then a portion is placed on a counting chamber, such as a hemocytometer. By counting the number of blue and clear cells, scientists can calculate the percentage of live cells in the sample, providing essential information for various experiments and applications.