Lithium ion specific fluorescent reversible extraction-release based on spiropyran isomerization combining crown ether coordination and its bioimaging

Lithium is a potent mood stabilizer and has unusual clinical, pharmacological, and biochemical properties. Therefore, it is of great significance to develop fluorescent probes to monitor Li+ in living cells visually. The emission wavelength of the reported Li+ fluorescent probes was mostly in the short-wave region, which is greatly interfered by the biological background fluorescence and not suitable for biological imaging. In view of the above shortcomings, we constructed a red emitted fluorescent probe by utilizing the spiropyran derivative as fluorophore and integrating the aza-12-crown-4 as the recognition site of Li+. Li+ induced the isomerization of spiropyran (fluorescent emission) to release oxygen negative ions, which combined with the coordination effect of crown ether to realize the specific fluorescence detection of lithium ion. The system was used for biological imaging in Hela cells and zebrafish. We believe that the current project will provide an effective visualization tool for studying the biological functions of lithium ions.