Highly sensitive fluorescent sensor for hypochlorite in nearly 100% aqueous solution and its application for live-cell, plant and zebrafish imaging

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 1 H NMR, TLC , FTIR, HRMS , UV–vis, fluorescence and DFT illustrated that ClO − reacted with the C C 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.