A novel high signal-to-noise ratio fluorescent probe for real-time mitochondrial viscosity detection and imaging in vitro and in vivo

Mitochondrial viscosity serves as a critical indicator for assessing mitochondrial functionality and offers valuable insights into cellular homeostasis. Continuous, real-time monitoring of mitochondrial viscosity is indispensable for understanding and diagnosing diseases associated with these dynamic changes. In this study, we introduce a novel mitochondrial viscosity-responsive probe named "<bold>JL-JC</bold>" which is designed by using a molecular strategy, with a classic "D-pi-A" molecular structure. Leveraging the distinctive twisted intramolecular charge transfer (TICT) properties of the probe, <bold>JL-JC</bold> exhibits exceptional sensitivity and a high signal-to-noise ratio, enabling precise detection of viscosity variations within its microenvironment while remaining unaffected by other factors. Upon rapid cellular uptake, <bold>JL-JC</bold> can efficiently evaluate the mitochondrial viscosity changes under diverse physiological and pathological conditions. Notably, this probe also enables viscosity imaging in zebrafish, offering insights into mitochondrial states in vivo. Our findings present <bold>JL-JC</bold> as a promising tool and potential diagnostic platform for mitochondria-related diseases.