Label-free fluorescence detection of mercury ions based on thymine-mercury-thymine structure and CRISPR-Cas12a

作者：Huang, Ruoying; Li, Mengyan; Qu, Zenglin; Liu, Yang; Lu, Xiaoxing; Li, Ruimin; Zou, Li^*

来源：Food Research International, 2024, 180: 114058.

DOI：10.1016/j.foodres.2024.114058

• Fluorescence
• Mercury ions
• Thymine-mercury-thymine
• CRISPR-Cas12a
• G-quadruplex

In this work, we developed a novel label -free fluorescent sensor for the highly sensitive detection of mercury ions (Hg2+) based on the coordination chemistry of thymine-Hg2+-thymine (T-Hg2+-T) structures and the properties of CRISPR-Cas12a systems. Most notably, two T -rich sequences (a blocker and an activator) were designed to form stable double -stranded structures in the presence of Hg2+ via the T-Hg2+-T base pairing. The formation of TT mismatched double -stranded DNA between the blocker and the activator prevented the cleavage of G -rich sequences by Cas12a, allowing them to fold into G-quadruplex-thioflavin T complexes, resulting in significantly enhanced fluorescence. Under the optimized conditions, the developed sensor showed an excellent response for Hg2+ detection in the linear range of 0.05 to 200 nM with a detection limit of 23 pM. Moreover, this fluorescent sensor exhibited excellent selectivity and was successfully used for the detection of Hg2+ in real samples of Zhujiang river water and tangerine peel, demonstrating its potential in environmental monitoring and food safety applications.

• 单位
  广东药学院; 1