A trans-Ferulic acid based fluorescence "turn-on" chemosensor for aluminum (III) ions in live cells and environmental samples

This study introduces a novel fluorescence 'turn-on' chemosensor, FHDA, based on a trans-Ferulic acid Schiff-base derivative. FHDA stands out as a highly selective and sensitive tool for the fluorescent detection of Al3⁺ with the fluorescence 'turn-on' effect. FHDA exhibits a strong CHEF effect and ICT upon complexation with Al³⁺ in a 1:2 binding stoichiometry. The significant Stokes shift (Δλ = 108 nm, λ_ex = 422 nm, λ_em = 530 nm), large binding constant (K_a = 4.2 × 10⁴ M^-1), ∼9.5-fold increase in the quantum yield (FHDA, Φ = 0.020; FHDA-Al³⁺ complex, Φ = 0.189), and a LOD of 134 nM, makes FHDA an excellent chemosensor for detecting Al³⁺ in solution; tests in live cells and environmental samples also showed excellent responses. FHDA offers substantial improvements over existing methods with its ease of use, limited expense, high specificity, and the ability to provide real-time, in-situ monitoring of Al³⁺ ions. The utility of FHDA is highlighted through applications in monitoring Al³⁺ ions in e.g. lung cancer cells (A549) and environmental water samples. We believe that applications of FHDA can potentially lead to a novel diagnostic and therapeutic strategy against diseases linked to aluminum dysregulation.