Linear Schiff-base fluorescence probe with aggregation-induced emission characteristics for Al3+ detection and its application in live cell imaging

- A new Schiff-base fluorescent probe based on AIE characterization for detecting Al3+ was synthesized.
- The probe 1 displayed a high selectivity and sensitivity toward Al3+ over many common metal ions in a complex mixture.
- The probe 1 toward Al3+ displayed fluorescence enhanced response based on AIE characterization.
- The probe 1 exhibited good biocompatibility, which had been applied for detecting Al3+ in live HeLa cells with satisfactory results.

A simple Schiff-base derivative with salicylaldehyde moieties as fluorescent probe 1 was reported by aggregation-induced emission (AIE) characterization for the detection of metal ions. Spectral analysis revealed that probe 1 was highly selective and sensitive to Al3+. The probe 1 was also subject to minimal interference from other common competitive metal ions. The detection limit of Al3+ was 0.4 μM, which is considerably lower than the World Health Organization standard (7.41 μM), and the acceptable level of Al3+ (1.85 μM) in drinking water. The Job's plot and the results of 1H-NMR and FT-IR analyses indicated that the binding stoichiometry ratio of probe 1 to Al3+ was 1:2. Probe 1 demonstrated a fluorescence-enhanced response upon binding with Al3+ based on AIE characterization. This response was due to the restricted molecular rotation and increased rigidity of the molecular assembly. Probe 1 exhibited good biocompatibility, and Al3+ was detected in live cells. Therefore, probe 1 is a promising fluorescence probe for Al3+ detection in the environment.