An innovative fluorescent probe based on dicyanoisoflurone derivatives for differential detection of Hg2+ and Cu2+ and its applications in bacteria, cell imaging and food analysis

Abstract

Background: Heavy metal pollution has become one of the world's most important environmental pollution, especially Hg²⁺ 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 Hg²⁺ 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 Hg²⁺, Cu²⁺ often interferes. Therefore, it is of great practical significance to synthesize a fluorescent probe that can distinguish between Hg²⁺ and Cu²⁺.

Results: We have successfully synthesized the probe DFS, a fluorescent probe that can differentially detect Hg²⁺ and Cu²⁺, and the probe DFS has good selectivity and anti-interference ability for Hg²⁺ and Cu²⁺. The fluorescence intensity at 530 nm increased rapidly when Hg²⁺ was detected; during the Cu²⁺ detection, the fluorescence intensity at 636 nm gradually decreased, fluorescence quenching occurred, and the detection limits of Hg²⁺ and Cu²⁺ 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 Hg²⁺ and Cu²⁺ 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 Hg²⁺ and Cu²⁺ detection in actual samples.

Significance and novelty: This is a fluorescent probe that can distinguish between Hg²⁺ and Cu²⁺, the fluorescence emission peak appears at 530 nm when Hg²⁺ is detected; when detecting Cu²⁺, fluorescence quenching occurs at 636 nm, the fluorescence emission peak distance between Hg²⁺ and Cu²⁺ differs by 106 nm. This reduces mutual interference between Hg²⁺ and Cu²⁺ during detection, it provides a new idea for the detection of Hg²⁺ and Cu²⁺.

Keywords: Bacterial imaging; Cell imaging; Copper ions; Differential detection; Mercury ions.