Asymmetric Heptamethine Quinocyanines with Large Stokes Shifts for High-Fidelity Imaging of Mitochondrial Viscosity and NAFLD

Abstract

Mitochondrial viscosity strongly correlates with its function. In this study, we designed and synthesized two asymmetric heptamethine quinocyanine dyes (QCy7-1 and QCy7-2). QCy7-1 exhibits viscosity-activated fluorescence (λ_em = 780 nm; Stokes shift = 239 nm) and a 20.8-fold brightness increase in glycerol versus PBS. Probe QCy7-1 enabes real-time monitoring of mitochondrial viscosity changes induced by nystatin, monensin, lipopolysaccharide, and starvation, and in vivo imaging of non-alcoholic fatty liver disease.