An innovative fluorescent probe based on dicyanoisoflurone derivatives for differential detection of Hg 2+ and Cu 2+ and its applications in bacteria, cell imaging and food analysis.

Background: Heavy metal pollution has become one of the world's most important environmental pollution, especially Hg ²⁺ is enriched, it is easy to enter the human body through the food chain, bind to the sulfhydryl group in the protein, cause mercury poisoning. Traditional methods for detecting Hg ²⁺ have obvious drawbacks, such as poor selectivity and long detection time. Fluorescence detection has attracted attention because of its good sensitivity and specificity detection ability. In previously reported probes for detecting Hg ²⁺ , Cu ²⁺ often interferes. Therefore, it is of great practical significance to synthesize a fluorescent probe that can distinguish between Hg ²⁺ and Cu ²⁺ .
Results: We have successfully synthesized the probe DFS, a fluorescent probe that can differentially detect Hg ²⁺ and Cu ²⁺ , and the probe DFS has good selectivity and anti-interference ability for Hg ²⁺ and Cu ²⁺ . The fluorescence intensity at 530 nm increased rapidly when Hg ²⁺ was detected; during the Cu ²⁺ detection, the fluorescence intensity at 636 nm gradually decreased, fluorescence quenching occurred, and the detection limits of Hg ²⁺ and Cu ²⁺ were 7.29 × 10 ^-9  M and 2.13 × 10 ^-9  M, respectively. Through biological experiments, it was found that probe DFS can complete the fluorescence imaging of Hg ²⁺ and Cu ²⁺ in Staphylococcus aureus and HUVEC cells, which has certain research value in the field of environmental monitoring and microbiology, and the probe DFS has low cytotoxicity, so it also has broad application prospects in the field of biological imaging. In addition, the probe DFS also has good applicability for Hg ²⁺ and Cu ²⁺ detection in actual samples.
Significance and Novelty: This is a fluorescent probe that can distinguish between Hg ²⁺ and Cu ²⁺ , the fluorescence emission peak appears at 530 nm when Hg ²⁺ is detected; when detecting Cu ²⁺ , fluorescence quenching occurs at 636 nm, the fluorescence emission peak distance between Hg ²⁺ and Cu ²⁺ differs by 106 nm. This reduces mutual interference between Hg ²⁺ and Cu ²⁺ during detection, it provides a new idea for the detection of Hg ²⁺ and Cu ²⁺ .
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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