Highly sensitive fluorescent sensor for hypochlorite in nearly 100% aqueous solution and its application for...

A new ICT type D-π-A structured chemosensor DTB derived from a bithiophene-benzothiazole derivative has been synthesized. Sensor DTB showed a colorimetric and fluorometric dual-signaling response to hypochlorite (ClO^-) in EtOH/HEPES solution (1/99, V/V, pH = 7.4, nearly 100% aqueous solution). Sensor DTB exhibited well specificity, high sensitivity and rapidity (<1 min) for ClO^- with a detection limit of 25 nM. Sensor DTB features remarkable color changes and significant fluorescence "turn-on" response (ca. 45 fold) after treating with ClO^-. Comprehensive analyses by ¹H NMR, TLC, FTIR, HRMS, UV-vis, fluorescence and DFT illustrated that ClO^- reacted with the CC bond of DTB, generating fluorophore 2T-CHO, leading to strong blue fluorescence. Interestingly, DTB loaded colorimetric test strips were established for rapid and real-time visual detection of ClO^-. Furthermore, the DTB was successfully applied to quantitatively and sensitively detect ClO^- in 84 disinfectant, bio-fluids (human serum and urine) and actual water samples. Importantly, the biocompatible DTB has been employed for visualizing and bioimaging ClO^- in mung bean sprouts, Arabidopsis, live cells and zebrafish. These investigations demonstrate that DTB has great potentials for detecting ClO^- in various biosystems and environments. This work would offer a new idea for developing multifunctional sensors with better performance for chemo/biosensors.