A novel mitochondria-targeted near-infrared (NIR) probe for detection of viscosity changes in living cell, zebra fishes and living mice

Viscosity is a key factor that determines the diffusion-controlled processes in biological systems. The matrix of mitochondria contains various enzymes and other proteins with high density, and the diffusion of which are severely restricted by the cristae, making it the most crowded place in the cells. Herein, we reported a new near-infrared probe NV-1 with increased Stokes shift for monitoring viscosity changes in mitochondria. A remarkable increase of the fluorescence was observed in glycerol compared with which was observed in methanol at 744 nm. The probe was applied for measuring viscosity changes not only in mitochondria, but also in vivo (in zebra fishes and mice).