Fluorous Soluble Cyanine Dyes for Visualizing Perfluorocarbons in Living Systems

The bioorthogonal nature of perfluoro­carbons provides a unique platform for introducing dynamic nano- and microdroplets into cells and organisms. To monitor the localization and deformation of the droplets, fluorous soluble fluoro­phores that are compatible with standard fluorescent protein markers and applicable to cells, tissues, and small organisms are necessary. Here, we introduce fluorous cyanine dyes that represent the most red-shifted fluorous soluble fluoro­phores to date. We study the effect of covalently appended fluorous tags on the cyanine scaffold and evaluate the changes in photophysical properties imparted by the fluorous phase. Ultimately, we showcase the utility of the fluorous soluble pentamethine cyanine dye for tracking the localization of perfluoro­carbon nano­emulsions in macrophage cells and for measurements of mechanical forces in multicellular spheroids and zebrafish embryonic tissues. These studies demonstrate that the red-shifted cyanine dyes offer spectral flexibility in multiplexed imaging experiments and enhanced precision in force measurements.