Synthesis and cell imaging studies of an unusual "OFF-ON" fluorescent sensor containing a triazole unit for Al detection via selective imine hydrolysis.

Monitoring excess Al 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 Al recognition is essential. Herein, we present the design of a new fluorescent molecule, A1, for the recognition of Al. The results indicated that the recognition mechanism of the imine hydrolysis of A1 for Al was completely different from those of other Al probes that function based on chelation-enhanced fluorescence. A1 demonstrated a highly selective fluorescence response in the "OFF-ON" mode toward the presence of Al 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 Al 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 Al proved that it can be exploited as a signal tool for environmental and biological samples.