A novel NIR probe for detection of viscosity in cellular lipid droplets, zebra fishes and living mice

Lipid droplets (LDs) are organelles which storage the lipids for all organisms. They are involved in many biological processes. LDs stored neutral lipids consisting of triglycerides, steryl esters, and retinyl esters. Herein, we constructed a novel NIR viscosity probe NLV-1 for monitoring the viscosity changes in biological systems. The probe NLV-1 showed a very strong fluorescence emission at around 719 nm in viscous media, the fluorescence intensity of the probe NLV-1 increased 13.77-fold from methanol to 99% glycerol. Moreover, the probe NLV-1 have been successfully utilized for monitoring the viscosity changes in cellular lipid droplets, and in zebra fishes. More importantly, we utilized the probe for measuring the viscosity variations in living mice.