Cellular Sensors, Ion and pH Indicators

The maintenance of inorganic cation and anion concentrations is a feature of live cells. Homeostatic regulation of these ionic gradients is critical for most cellular functions. Measuring ionic concentrations with both spatial and temporal resolution has become critical in research, ranging from drug discovery to studies of neuronal function. Fluorescent probes, which allow visualization of cations (e.g. Ca2+, Zn2+, Mg2+), anions (e.g. Cl−, Phosphate), pH shifts, membrane potentials or enzymatic activity in live cells by fluorescence microscopy, are useful tools for studying biological systems.