Fluo-4

Fluo-4 is a specially designed dye used by scientists to observe calcium levels inside cells. When it enters a cell, it reacts with calcium ions, causing it to fluoresce—or glow—under a microscope with a specific light. Because calcium signals are crucial for many cellular functions, Fluo-4 helps researchers visualize and measure these rapid, dynamic changes in calcium concentration, providing insight into processes like muscle contraction, nerve activity, and cell communication. Its brightness and sensitivity make it a valuable tool for studying how cells behave in real-time.