A Benzothiazole-Based Fluorescent Probe for Ratiometric Detection of Al³⁺ in Aqueous Medium and Living Cells

Abstract

Aluminum is the third (after O and Si) most abundant metal in the earth’s crust and associates with neurological diseases when abnormal level of Al3+ occurs in nervous center. Developing highly sensitive and selective methods for Al3+ detection is of significant interest. In this work, we developed an excited state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE) active fluorescent probe for ratiometric detection of Al3+ in aqueous medium and living cells. The BTZ-SF can detect Al3+ with high selectivity and a good linear relationship (R2 = 0.9911) between fluorescence intensity ratio (I476 nm/I568 nm) and Al3+ concentration (0–100 μM). In addition, the detection limit was calculated as low as 2.2 μM. The single crystal structure of BTZ-SF–Al clearly exhibited the interaction between BTZ-SF and Al3+ with a hexa-coordinated structure. Furthermore, confocal fluorescence images of HeLa cell indicated that BTZ-SF could be used for monitoring Al3+ in living cells. Finally, a test strips experiment suggests that the BTZ-SF can recognize the Al3+ selectively accompanied by remarkable color change.