Pentamethinium fluorescent probes: The impact of molecular structure on photophysical properties and subcellular localization

The performance of fluorescent probes arises from their structural basis. In this study, we report design and synthesis of a series of novel symmetrical gamma-substituted pentamethinium fluorescent probes. Relationship between structure, photophysical properties and intracellular localization was explored and structural variations resulting in high photostabillity and selectivity for subcellular localization were obtained. Substitution of benzothiazolium moieties on both sides of the pentamethinium chain for indolium units led to red shift in the absorption and fluorescence emission maxima of the probe and increased photostability. The major advantage of the probes with side indolium units is their mitochondrial specificity, high photostability and synthetic accessibility. (C) 2014 Elsevier Ltd. All rights reserved.