Lutidine derivatives for live-cell imaging of the mitochondria and endoplasmic reticulum

The mitochondria and endoplasmic reticulum (ER) are highly dynamic subcellular structures essential for several biological functions. The development of non-toxic, wash-free fluorophores to visualize these structures inside cells aid in understanding their localization and dynamics in diverse cellular processes. In this paper, we report the synthesis and characterization of lutidine-based cationic fluorophores bearing push-pull substituents exhibiting emission in green and red wavelength regions and their subcellular localization in living cells. The confocal imaging of the molecules in a cellular domain reveals the robust localization of three molecules (2, 4 and 5) in the mitochondria and two molecules with polyfluorophenyl substituents (6 and 7) in the ER. At the same time, the other two molecules (1 and 3) showed non-specific imaging. These molecules can also be used to sense the altered viscosity of the stressed ER and investigate its dynamics.