Branch-Migration Based Fluorescent Probe for Highly Sensitive Detection of Mercury

Area of Science:

• Analytical Chemistry
• Environmental Science
• Biochemistry

Background:

• Heavy metal detection is crucial for food safety and environmental monitoring.
• Mercury ion (Hg2+) is a prevalent and toxic heavy metal requiring sensitive detection methods.
• Traditional T-Hg-T based assays for mercury detection are limited by low sensitivity due to reliance on multiple T-Hg-T interactions.

Purpose of the Study:

• To develop a highly sensitive fluorescent probe for mercury ion detection.
• To overcome the limitations of traditional T-Hg-T based assays.
• To demonstrate the probe's applicability in real-world environmental and food samples.

Main Methods:

• Development of a novel branch-migration based fluorescent probe utilizing a single T-Hg-T interaction.
• Exploration of sensing mechanisms in different reaction modes (first-order and mixed).
• Incorporation of Endonuclease IV for signal amplification and assessment of specificity against interfering ions.

Main Results:

• The single T-Hg-T interaction enabled strong signal generation.
• Detection limits of 18.4 nM and 14.7 nM were achieved in first-order and mixed reaction modes, respectively.
• Endonuclease IV assisted amplification reduced the detection limit to 1.2 nM, outperforming many DNA-based fluorometric assays.
• The probe demonstrated high specificity and accurate mercury detection in deionized and lake water samples, comparable to atomic fluorescence spectrometry.

Conclusions:

• The proposed branch-migration fluorescent probe offers a sensitive and practical method for mercury ion detection.
• This novel approach surpasses traditional T-Hg-T assays by utilizing a single T-Hg-T interaction for enhanced signal output.
• The probe shows significant potential as a substitute for existing DNA probes in food safety and environmental analysis.