A simple "turn-on" fluorescent sensor for reversible recognition of aluminum ion in living cell.

A simple and reliable "turn-on" fluorescent sensor (E)-1-[((2-hydroxyethyl)imino) methyl] naphthalen-2-ol (HNP) has been designed, synthesized, and characterized by 1H-NMR, 13C-NMR, FT-IR, and EI-MS analysis. The binding property of HNP was examined employing UV-Vis and fluorescence spectroscopy. HNP exhibited high selectivity towards Al3+ among other cations and anions. The fluorescence titration experiment has established binding stoichiometry of HNP with Al3+ is 2:1, which can be further verified by HR-MS. The detection limit of HNP is 2.9 μM, and it can be reversible five-to-seven times to detect Al3+ without losing much efficiency which indicates that it can be a reliable probe for Al3+. Additionally, HNP was successfully applied for the detection of Al3+ in living cells. To achieve the detection of aluminum ion across a simple, reliable, and precise method, we have investigated the reversible detection (which can reversible response to Al3+ for five-to-seven times) of Al3+ through an extremely simple (requires only one-step reaction) "turn-on" fluorescent probe which enables us to visualize and analyze Al3+ with low detection limit (2.9 μM) and high selectivity in living cell without interference from the high abundant small biological molecules.