A Novel Reversible Fluorescent Probe for Sequential Detection of Aluminium Ion and PPi and Bioimaging in Living Cells

In this study, we have successfully synthesized a novel probe HL by condensation reaction of acetophenone with 8-hydroxyquinoline-2-carbaldehyde derivative and its structure was characterized by H-1 NMR, C-13 NMR, IR and HRMS. The probe HL displayed highly selective and sensitive fluorescence "turn on" response as well as naked-eye color change towards Al3+ in the presence of other competing cations in DMF-HEPES (5:1, v/v, 10 mM, pH=7.2). The binding mechanisms have been explored though Job's plot, HRMS, H-1 NMR and theoretical calculations, which was ascribed to photoinduced electron transfer process (PET) and chelation-enhanced fluorescence mechanism (CHEF). The ensemble HL-Al3+ displayed high selectivity to PPi (P2O74-, pyrophosphate) through pulling out Al3+ and releasing free probe HL in physiological conditions. The sensing process was reversible. Furthermore, the cells imaging experiences showed that probe HL could be use as relay on detection of Al3+ and PPi in living PC12 cells.