A fluorogenic sensor for in situ tracking of viscosity in response to cellular inflammatory stress

Abstract

Exploring the changes in intracellular viscosity in response to inflammatory stress is of great significance for the detection and treatment of various diseases. For this purpose, we synthesized a viscosity-sensitive fluorescent probe VisP, which was constructed with carbazole as the fluorophore and indole salt as the rotor. The probe VisP emitted weak red fluorescence in low viscosity media, and strong red fluorescence in highly viscous solvents, exhibiting a drastic viscosity dependence and linear correlation (R² = 0.996). The spectral tests and cell imaging experiments jointly confirmed the satisfactory photostability of the VisP. In addition, the MTT test results showed that the probe has low cytotoxicity, further supporting the application prospect of the probe in biological systems. By using the probe VisP, changes in the viscosity in nystatin and monensin-induced cells were tracked in situ, revealing the phenomenon of increased physiological viscosity in response to inflammatory stress. Moreover, the fluctuation of viscosity in dexamethasone sodium phosphate treated inflamed cells has also been sensed. This work not only provides an important tool for inflammation research, but also provides a new perspective for the study of viscosity-related diseases.