A turn-on fluorescent sensor for imaging labile Fe(3+) in live neuronal cells at subcellular resolution.

An eye for an iron: A highly sensitive, selective and reversible turn-on Fe(3+) sensor for imaging labile Fe(3+) in live cells at subcellular resolution is reported. The sensor can respond to changes in intracellular Fe(3+) levels and was used to image endogenous chelatable Fe(3+) in live human neuroblastoma SH-SY5Y cells, with two Fe(3+) pools being identified in mitochondria and endosomes/ lysosomes for the first time.