Calcein AM/PI Live-Dead Cell Staining Kit is a reagent kit used to distinguish between viable mammalian cells with esterase activity and dead cells The kit contains two probes Calcein AM and Propidium Iodide (PI) Calcein AM is a probe that stains live cells it is a derivative of Calcein with an added AM moiety which makes it more hydrophobic and allows better cell permeability Calcein AM itself is non-fluorescent but once it enters live cells it is hydrolyzed by intracellular esterases into Calcein which can emit strong green fluorescence PI is a probe for dead cells which enters only cells with compromised membranes staining them red The fluorescence intensities of these two probes reflect cell viability and toxicity The kit is easy to use 30 minutes of staining incubation After staining results can be detected using fluorescence microscopy fluorescence microplate readers or flow cytometry This kit is unsuitable for bacteria or fungi