A highly selective turn-on fluorescent probe for Al(iii) based on coumarin and its application in vivo

Abstract

In this study, a turn-on coumarin-based fluorescent probe, 7-hydroxy-6-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-4-methyl-chroman-2-one (CN), was developed for detecting Al³⁺ in aqueous systems. The binding ratio of CN–Al³⁺ complexes was determined from the Job plot and ESI-MS data to be 1 : 1. The binding constant (K_a) of Al³⁺ binding to CN was calculated to be 9.55 × 10⁴ M⁻¹ from a Benesi–Hildebrand plot and the detection limit was evaluated to be as low as 0.10 μM (LOD = 3σ/slope). CN could be used as an effective fluorescent probe for detecting Al³⁺ in living HeLa cells. Moreover, CN could also be applied in the in vivo detection of Al³⁺ in zebrafish.