Salicylimine-based fluorescent chemosensor for aluminum ions and application to bioimaging

In this study, an assay to quantify the presence of aluminum ions using a salicylimine-based receptor was developed utilizing turn-on fluorescence enhancement. Upon treatment with aluminum ions, the fluorescence of the sensor was enhanced at 510 nm due to formation of a 1:1 complex between the chemosensor and the aluminum ions at room temperature. As the concentration of Al ³⁺ was increased, the fluorescence gradually increased. Other metal ions, such as Na ⁺, Ag ⁺, K ⁺, Ca ²⁺, Mg ²⁺, Hg ²⁺, Mn ²⁺, Co ²⁺, Ni ²⁺, Cu ²⁺, Zn ²⁺, Cd ²⁺, Pb ²⁺, Cr ³⁺, Fe ³⁺, and In ³⁺, had no such significant effect on the fluorescence. In addition, we show that the probe could be used to map intracellular Al ³⁺ distribution in live cells by confocal microscopy.