A molecular scaffold for concurrent targeting of plasma and mitochondrial membranes

The ability to specifically sense and image plasma membranes and mitochondrial membranes with fluorescent probes is paramount for the visualization and mechanistic understanding of these fundamental, dynamic cellular compartments. However, dual-targeting membrane probes combining a fluorophore and two distinct targeting ligands face synthetic challenges and potential functional group interference. Therefore, we designed a molecular scaffold (dual-targeting ligand) that combines both a mitochondrial anchor and a plasma membrane protein ligand to simultaneously localize at both membranes. Using this molecular scaffold, we engineered a series of fluorescent probes, T-1 to T-5. Furthermore, we demonstrate the functional applications of two probes from this series, T-1 and T-4. Owing to the distinct physicochemical properties of the targeted plasma and mitochondria membrane, T-1 can differentiate multiple cell states, including live, dead, and early apoptotic cells. Additionally, T-4, designed as a dual-targeting photosensitizer, induces cancer cell necrosis by simultaneously rupturing the plasma membrane and inducing mitochondrial swelling, leading to enhanced photosensitizing efficiency. Significantly, this research advances the development of fluorescent probe based labeling strategies and provides effective tools for biochemical and biomedical applications.