Thermo Fisher, 15250061, Trypan Blue Solution, 0.4%

Gibco Trypan Blue Solution 0.4% is a ready-to-use dye for rapid evaluation of cell viability by membrane exclusion. Cells with intact plasma membranes generally exclude trypan blue, while cells with compromised membranes take up the dye and appear blue during bright-field microscopy. The staining reaction is commonly used with a hemocytometer during mammalian cell counting, passaging and preparation of experiments requiring a known viable-cell concentration. This presentation contains 100 mL of sterile-filtered 0.4% solution. Mix cells with the staining solution at the ratio specified by the chosen counting method, then assess the sample promptly to reduce changes associated with prolonged dye exposure. Count viable and nonviable cells using a consistent counting rule and calculate both concentration and percent viability. The dye is not a direct measure of metabolic activity or apoptotic state. Keep the reagent closed and protected from contamination, and store at 15–30 °C. Appropriate gloves and laboratory practices are required when handling dye and cell specimens.