A ratiometric fluorescent chemosensor for Al³⁺ in aqueous solution based on aggregation-induced emission and its application in live-cell imaging.

A ratiometric fluorescent chemosensor 1 was developed for the detection of Al(3+) in aqueous solution based on aggregation-induced emmision (AIE). The chemosensor showed the fluorescence of its aggregated state and Al(3+)-chelated soluble state in the absence and in the presence of Al(3+), respectively, and resulted in a fluorescence ratio (I461/I537) response to Al(3+) in neutral aqueous solution at a detection limit as low as 0.29 μmol L(-1). The method was also highly selective to Al(3+) over other physiological relevant metal ions investigated in this study. Taking advantage of its AIE characteristics, the chemosensor was successfully applied on test papers for simple and rapid detection of Al(3+). Moreover, the application of 1 for the imaging of Al(3+) in living cells by ratiometric fluorescence changes was also achieved.