A colorimetric/ratiometric chemosensor based on an aggregation-induced emission strategy for tracing hypochlorite in vitro and in vivo.

Excessive levels of hypochlorite (ClO) negatively affect environmental and biological systems. Thus, it is essential to develop sensors that can identify ClO in various systems such as the environment and living organisms. In this study, we report the development and evaluation of a novel aggregation-induced emission (AIE) strategy-based colorimetric and ratiometric fluorescent chemosensor 2,2'-(((1E,1'E)-[2,2'-bithiophene]- 5,5'-diylbis(methanylylidene))bis(hydrazin-1-yl-2-ylidene))bis(N,N,N-trimethyl-2-oxoethan-1-aminium) chloride (BMH-2∙Cl) for detecting ClO. BMH-2∙Cl enabled highly selective ClO detection through a color change from yellow to colorless and a fluorescence color change from turquoise to blue in a perfect aqueous solution. BMH-2∙Cl exhibited low limits of detection (2.4 ×10 M for colorimetry and 2.9 ×10 M for ratiometric fluorescence) for detecting ClO with a rapid response within 5 s. The detection mechanism for ClO and an AIE property change of BMH-2∙Cl were demonstrated by H NMR titration, ESI-MS, variation of water fraction (f) and theoretical calculations. In particular, we confirmed not only the practicality of BMH-2∙Cl by using test strips, but also demonstrated the potential for efficient ClO detection in biological and environmental systems such as real water samples, living zebrafish and bean sprouts.