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

Development of a novel near-infrared (NIR) probe for detection toxic Hg2+ in biosome with high selectivity and sensitivity, are of great interest but remains a great challenge. Hence, in this work, a new NIR fluorescent enhance sensor (TBBA)，which contained a D-A structure as the NIR fluorophore and rhodanine-3-acetic acid as the receptor has been developed for detection 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. Further, TBBA is applicable as a fluorescent probe for imaging in living cells and zebrafish, indicating that it can be potentially applied for Hg2+ sensing in both environmental and biology fields.