Described herein are materials and methods for measuring intracellular ion concentrations, materials and methods for identifying modulators of intracellular ion concentrations, modulators if intracellular ion concentration, use of modulators of intracellular ion concentration to treat a disease or disorder associated with aberrant intracellular ion concentrations, and cell lines and transgenic animals that express a fluorescent ion detector and/or one or more ion transport proteins or ion channels.
