A novel benzothiadiazole-based and NIR-emissive fluorescent sensor for detection of Hg2+ and its application in living cell and zebrafish imaging

Abstract

The development of a novel near-infrared (NIR) probe for the detection of toxic Hg²⁺ in organisms with high selectivity and sensitivity is of great interest but remains a great challenge. Hence, in this work, a new NIR fluorescence enhanced sensor (TBBA), which contains a D–A structure as the NIR fluorophore and rhodanine-3-acetic acid as the receptor, has been developed for the detection of Hg²⁺ with high selectivity, sensitivity, low limit of detection (13.10 nM) and good binding constant (2.37 × 10⁴ M⁻¹). The mechanism of TBBA response to Hg²⁺ was further proved by ¹H NMR titration, HRMS, and theoretical calculations. Furthermore, TBBA is applied as a fluorescent probe for imaging living cells and zebrafish, indicating that it can be potentially applied for Hg²⁺ sensing in both environmental and biology fields.