TICT improved NIR emission and lysosome-specific functional dye visualizing viscosity in disease model

Since the dependence of ferroptosis on autophagy was discovered, the cross-linking between ferroptosis and autophagy has received much attention. Studies have shown that lysosomes are not only important participants in the autophagy process, but also iron storage hubs in organisms. Meanwhile, lysosome dysfunction has been shown to be one of the causes of ferroptosis. However, the connection between autophagy and ferroptosis is still obscure. Previous studies have revealed the relationships between viscosity and autophagy, as well as viscosity and ferroptosis, respectively. Therefore, viscosity may be a link between autophagy and ferroptosis. In this work, we developed a fluorescence probe (IG-Lyso) with the near infrared (emission wavelength of 825 nm) activated by viscosity, which was specifically captured by the lysosome through endocytosis. IG-Lyso was used to monitor lysosomal viscosity in the autophagy and ferroptosis processes. The experiment showed that autophagy was induced during ferroptosis, accompanied by an increase in viscosity. In addition, IG-Lyso had been successfully used to delineate the contours of tumor lesions by utilizing its high sensitivity to viscosity, thus achieving the purpose of tumor identification. We anticipate that this research not only provides a new idea to elucidate the connection between ferroptosis and autophagy, but also provides a new tool for direct navigation of tumor lesions in clinical applications.