A benzothiazole-based fluorescent probe for efficient detection and discrimination of Zn2+ and Cd2+, using cysteine as an auxiliary reagent

This paper describes the design and synthesis of a benzothiazole-based fluorescent probe (H-1) for zinc and cadmium ion detection and discrimination, using cysteine as an auxiliary reagent. Among the various metal ions tested, zinc and cadmium ions induced blue-shifted emissions of probe H-1 from 573 nm to 520 nm and 540 nm, respectively. The addition of cysteine caused the emission of H-1-Cd2+ to red-shift back to 573 nm. In contrast, the emission of H-1-Zn2+ with the addition of cysteine only decreased without anyred shift of wavelength. Furthermore, confocal laser scanning micrographs of HeLa cells demonstrated satisfactory cell permeability of H-1 and selectivity toward zinc and cadmium ions in living cells. Test strip experiments suggest that probe H-1 can recognise zinc and cadmium ions together by a remarkable fluorescence change, thus providing a convenient method for tracking zinc and cadmium ions in biological systems. (c) 2018 Elsevier B.V. All rights reserved.