A dual-channel colorimetric and ratiometric fluorescence chemosensor for detection of Hg2+ion and its bioimaging applications

A new colorimetric and ratiometric fluorescence chemosensor 4-((3-(octadecylthio)-1,4-dioxo-1,4-dihy dronaphthalen-2-yl)amino)benzenesulfonamide (4DBS) was synthesized and investigated for the selective detection of Hg2+ in DMSO-H2O (9:1, v/v) solution. The chemosensor was efficiently synthesized in two steps via Michael-like addition and nucleophilic substitution reactions. The ratiometric fluorescence turn-on response was obtained towards Hg2+, and its fluorescence emission peak was redshifted by 140 nm with an associated color change from light maroon to pale yellow due to the intramolecular charge transfer effect. The formed coordination metal complex was further evaluated by FT-IR, 1H NMR, and quantum chemical analyses to confirm the binding mechanism. The detection process was sensitive/reversible, and the calculated limit of detection for Hg2+ was 0.451 mM. Furthermore, 4DBS was effectively utilized as a bioimaging agent for detection of Hg2+ in live cells and zebrafish larvae. Additionally, 4DBS showed distinguishing detection of Hg2+ in cancer cells in comparison with normal cells. Thus, 4DBS could be employed as an efficient bioimaging probe for discriminative identification of human cancer cells. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

A new colorimetric and ratiometric fluorescence chemosensor 4-DBS was synthesized and investigated for selective detection of Hg2+. The sensor showed a ratiometric fluorescence turn-on response towards Hg2+, making it an effective probe for bioimaging applications.