Synthesis and cell imaging studies of an unusual “OFF–ON” fluorescent sensor containing a triazole unit for Al3+ detection via selective imine hydrolysis

Abstract

Monitoring excess Al³⁺ in biological and environmental samples is a major goal for scientists due to its harmful effects. Thus, the development of selective and convenient techniques for Al³⁺ recognition is essential. Herein, we present the design of a new fluorescent molecule, A1, for the recognition of Al³⁺. The results indicated that the recognition mechanism of the imine hydrolysis of A1 for Al³⁺ was completely different from those of other Al³⁺ probes that function based on chelation-enhanced fluorescence. A1 demonstrated a highly selective fluorescence response in the “OFF–ON” mode toward the presence of Al³⁺ among a pool of analytes including 18 cations with striking blue emission. Moreover, it has a prominent LOD value (0.117 μM), fast response time (10 s) and increasing linear emission relationship with Al³⁺ concentration (0–20.0 μM). Bioimaging studies in human colorectal carcinoma cells (DLD-1) and healthy epithelial cells (CCD-18Co) demonstrated excellent results. The performance of A1 toward Al³⁺ proved that it can be exploited as a signal tool for environmental and biological samples.