A robust xanthylium-based near-infrared fluorescent probe for viscosity imaging in inflammatory and hepatic injury mice models.

As the principal organ for the metabolism and detoxification of both exogenous and endogenous substances, the liver demonstrates heightened vulnerability to the onset of hepatic pathologies. Aberrant viscosity, acting as a potential biomarker, exhibits a significant correlation with liver diseases such as fatty liver, hepatic fibrosis, and liver injury. Therefore, real-time monitoring of viscosity fluctuations in animal models of liver disease is essential for related pathological investigations. Here, we report a novel viscosity-sensitive fluorescent probe (DJXP) with NIR excitation at 736 nm and emission at 809 nm, characterized by a large Stokes shift (67 nm), a broad operational pH range, high selectivity and excellent biocompatibility. DJXP enabled the visualization of viscosity changes in ICR mice induced by the antifungal drug nystatin, as determined by fluorescence imaging analysis. Furthermore, DJXP was employed to monitor elevated viscosity in mouse models of both lipopolysaccharide (LPS)-induced inflammation and rotenone-induced acute hepatic injury, demonstrating promising potential for the non-invasive detection and diagnosis of hepatic pathologies associated with altered viscosity.