A ratiometric fluorescence platform for lead ion detection via RNA cleavage-inhibited self-assembly of three-arm branched junction

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 298; p. 122787
• Main Authors: Li, Ying, Ma, Xinyue, Liu, Kai, Liu, Zheng, Zou, Ruiqi, Wang, Junyang, Yang, Chuanyu, Zheng, Hongru, Sun, Chunyan
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05.10.2023
• Subjects: Biosensing Techniques - methods; Catalytic hairpin assembly; DNA, Catalytic - chemistry; DNAzyme; Dual FRET; Humans; Ions; Lead; Limit of Detection; Pb2; Ratiometric fluorescence; Reproducibility of Results; RNA Cleavage; Ratiometric fluorescence; DNAzyme; Pb2; Catalytic hairpin assembly; Dual FRET; Pb(2+)
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2023.122787

[Display omitted] •A ratiometric platform for Pb2+ via RNA cleavage-inhibited CHA and dual FRET.•CHA-TBJ carried with FRET probes was used to simplify the design and procedure.•CHA-regulated ratiometric signal induced low background for sensitive detection.•Pb2+ analysis was achieved with favorable specificity, accuracy and applicability. Heavy metal pollution can pose a threat to food safety and human health, and accurate quantification of heavy metal ions is a vital requirement. Emerging DNA nanostructures-based biosensors offer attractive tools toward ultra-sensitive or rapid analysis of heavy metal ions. However, the problems including complex design, severe reaction conditions and undesirable reliability are inevitable obstacle in advancing their extension and application. Herein, a ratiometric fluorescent platform was established for monitoring lead ion (Pb2+) in food based on dual Förster resonance energy transfer (FRET) and RNA cleavage-inhibited self-assembly of three-arm branched junction (TBJ). GR-5 DNAzyme was employed for Pb2+ recognition, and enzyme-free amplification technique catalytic hairpin assembly (CHA) served to form FRET probes-carried TBJ. The substrate strand (S) of DNAzyme triggered the generation of CHA-TBJ, and Pb2+-responsive cleavage of S hindered the assembly of CHA-TBJ, causing opposite changes in the FRET states of FAM/BHQ1 and ROX/BHQ2 pairs. The fluorescence responses were recorded through synchronous fluorescence spectrometry to indicate Pb2+ concentration, allowing sensitive and reliable identification of Pb2+ in the linear range of 0.05–5 ng mL−1 with the detection limit of 0.03 ng mL−1. The Pb2+ detection can be achieved under conventional reaction conditions, simple mixing procedures and one-step measurement operation. The approach can afford excellent specificity for Pb2+ against competing metal ions, and can be applied to analyze Pb2+ in tea samples with satisfactory results. This facile fluorescence platform shows a capable method for Pb2+ detection, and provides new avenue in the development of ratiometric approaches and DNAzyme strategies for monitoring heavy metal pollution, facilitating the transformation of DNAzyme-based biosensors for food safety control.