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 H-NMR, C-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 Al among other cations and anions. The fluorescence titration experiment has established binding stoichiometry of HNP with Al 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 Al without losing much efficiency which indicates that it can be a reliable probe for Al. Additionally, HNP was successfully applied for the detection of Al 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 Al for five-to-seven times) of Al through an extremely simple (requires only one-step reaction) "turn-on" fluorescent probe which enables us to visualize and analyze Al with low detection limit (2.9 μM) and high selectivity in living cell without interference from the high abundant small biological molecules.