A highly selective turn-on fluorescent and naked-eye colorimetric sensor for cyanide detection in food samples and its application in imaging of living cells

Abstract

A novel highly selective oligothiophene-benzothiazole based sensor 3TBN has been developed for “naked-eye” colorimetric and fluorescent “turn-on” detection of cyanide in aqueous DMSO media. The sensor 3TBN exhibited distinct visual color and spectral changes in response to cyanide anion (CN−) over other tested anions. A good linear relationship was clearly observed between the fluorescence enhancement of the sensor 3TBN and the concentration of CN− in the wide range of 0–40 μM with a low detection limit of 0.46 μM. The sensing mechanism based on the nucleophilic addition reaction of the sensor with CN− on the cyanovinyl electrophilic CC group has been well confirmed. Economically viable paper-based colorimetric test strips of 3TBN were fabricated to effectively detect the CN− ions in water. More importantly, as a cost-effective and selective fluorescent sensor, the sensor 3TBN has been successfully employed for detection of CN− in food samples and fluorescence bioimaging in living HeLa cells.