Development of Highly Sensitive Fluorescent Probes for Detection of Intracellular Copper(I) in Living Systems

We describe here the new copper-selective fluorescent probes FluTPA1 and FluTPA2, in which the tetradentate ligand tris[(2-pyridyl)methyl]amine (TPA) is connected to a reduced form of a fluorescein platform through a benzyl ether linkage. These probes selectively react with copper ions in the presence of submillimolar glutathione and emit intense green fluorescence from the reaction product, O-methylfluorescein. Confocal images of live cells further show that FluTPA2 is membrane-permeable and allows visualization of Cu-I present in living cells.