Long-Term Mg²⁺ Imaging in Live Cells with a Targetable Fluorescent Probe

Living cells dynamically change their morphology and function according to the cell cycle. Long-term observations of living cells are privileged when we spy the unique, cell cycle-driven molecular events, which cannot be obtained from short-term ones. Mg²⁺, a metal ion abundant in cells, has been shown to be involved in a variety of physiological phenomena by noninvasive cellular observation using fluorescence microscopy. However, long-term observation of Mg²⁺ in cells has been a great challenge. Herein, we present a protocol for the long-term microscopic imaging of intracellular Mg²⁺ levels using a small molecule-protein hybrid fluorescent probe we developed.