A long wavelength fluorescent probe for detecting viscosity and its application in liquid foods and bioimaging

The viscosity of liquid food is a critical parameter of their quality and also closely linked to the onset of various diseases in biological systems. In this study, we have designed and synthesized a twisted intramolecular charge transfer (TICT)-based fluorescent probe (IDQL) to detect viscosity changes in liquid food as well as in cells and liver tissues. IDQL has demonstrated high sensitivity and selectivity, enabling the precise analysis of viscosity alterations in liver diseases models. Additionally, it has successfully identified viscosity changes induced by food thickener and been applied to track viscosity variations during the deterioration process of mango and peach juice. IDQL would well serve as a novel tool to monitor viscosity changes in liquid food during spoilage and could demonstrate its broad potential in both biomedical and food quality monitoring applications.