A near-infrared fluorescent probe for monitoring abnormal mitochondrial viscosity in cancer and fatty-liver mice model

Viscosity is an important component of cell microenvironment, and abnormal mitochondrial viscosity is associated with many diseases such as tumor and fatty liver. Herein, a near-infrared fluorescence probe (QX-V) based on quinoline-xanthene dye for detecting viscosity is constructed. In high viscosity medium, the free rotation of single bond is inhibited and the fluorescence is released. The probe shows high sensitivity together with good selectivity. Notably, QX-V has a long excitation wavelength (710 nm) and emission wavelength (786 nm). At the same time, the probe is a positively charged molecule that can target mitochondria. QX-V can not only distinguish cancer cells from normal cells, but also make a distinction between normal cells and fatty hepatocytes. In addition, QX-V is used to image viscosity abnormality in tumor-bearing mice. The probe also has a good ability to image viscosity abnormality caused by liver injury in fatty-liver mice.