Calcein-AM (CAS 148504-34-1)

Calcein-AM, with the CAS number 148504-34-1, is a non-fluorescent, cell-permeable compound widely utilized in biological research for assessing cell viability and cytotoxicity. The "AM" in its name stands for acetoxymethyl ester, which is a modification that allows the compound to permeate living cell membranes. Once inside the cell, esterases, which are hydrolytic enzymes abundant in cytoplasm, cleave the acetoxymethyl groups, converting Calcein-AM to calcein, a highly fluorescent compound. This conversion is crucial as it traps the fluorescent calcein inside healthy and viable cells, as calcein is membrane-impermeable. The resulting intense green fluorescence of calcein can be readily observed and measured using fluorescence microscopy or spectrophotometry, providing a robust indicator of live cell populations. This mechanism underlies the application of Calcein-AM in various research disciplines, where it serves as a vital tool for investigating cell proliferation, cytotoxicity assays, and multi-drug resistance phenomena. Additionally, its utility extends to the study of cell adhesion, migration, and invasion assays, as the fluorescence provides a quantitative and visual means to monitor and analyze these dynamic biological processes in real-time, without harming the cells. This attribute makes Calcein-AM an invaluable reagent in non-destructive cellular assays, enhancing our understanding of cellular mechanisms and behavior in vitro.