Fura-2 AM is widely used in biological research as a fluorescent indicator for measuring intracellular calcium levels. It is particularly valuable in live-cell imaging studies due to its ability to permeate cell membranes. Once inside the cell, esterases cleave the AM ester groups, trapping the Fura-2 dye intracellularly. This dye exhibits a shift in fluorescence emission when bound to calcium, allowing researchers to monitor calcium dynamics in real-time. Applications include studying calcium signaling in neurons, muscle cells, and other cell types, as well as investigating cellular responses to stimuli such as hormones, neurotransmitters, or drugs. Its high sensitivity and ratiometric measurement capability make it a preferred tool for precise calcium quantification in physiological and pathological conditions.