Fluorescence and electrochemical assay for bimodal detection of lead ions based on Metal-Organic framework nanosheets

Guozhen Chen; Wushuang Bai; Yan Jin; Jianbin Zheng

doi:10.1016/j.talanta.2021.122405

Fluorescence and electrochemical assay for bimodal detection of lead ions based on Metal-Organic framework nanosheets

Talanta. 2021 Sep 1:232:122405. doi: 10.1016/j.talanta.2021.122405. Epub 2021 Apr 19.

Authors

Guozhen Chen¹, Wushuang Bai², Yan Jin³, Jianbin Zheng⁴

Affiliations

¹ College of Chemistry & Materials Science, Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi'an, Shaanxi, 710069, China; Shaanxi Research Design Institute of Petroleum and Chemical Industry, Xi'an, Shaanxi, 710054, China.
² College of Chemistry & Materials Science, Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi'an, Shaanxi, 710069, China.
³ Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
⁴ College of Chemistry & Materials Science, Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi'an, Shaanxi, 710069, China. Electronic address: zhengjb@nwu.edu.cn.

PMID: 34074396
DOI: 10.1016/j.talanta.2021.122405

Abstract

The accurate measurement of heavy metal ions is essential for human health and environmental protection. Here, we report the design of a simple and convenient bimodal strategy for signal-on, label-free lead ion detection in environmental samples based on two-dimensional metal-organic framework (2D-MOF) nanosheets. 2D-MOFs have different affinities toward guanine-rich DNA (ssGDNA) and the G-quadruplex, allowing these structures to be distinguished. The nanosheets were also used as quenchers for fluorescent lead ion detection. Using lead ions to induce G-quadruplex formation from ssGDNA, a simple fluorescence resonance energy transfer (FRET) strategy was developed for lead ion detection; the detection limit was 3.3 nM. Based on changes in the GDNA configuration, the FRET system was converted into an electrochemical sensor for lead ion assays using an electrode modified with the 2D-MOF nanosheets. Electrochemical impedance spectroscopy showed a high sensitivity and a low limit of detection (i.e., 8.7 pM) of the electrode. The adaptability of the bimodal mechanism was verified through the successful detection of lead ions in tap water and fertilizer samples, and the method accuracy was demonstrated through inductively coupled plasma analysis. The developed bimodal device is cost-effective, highly sensitive, and allows for convenient operation, thereby rendering it a promising and reliable system for the detection of lead ions in environmental samples.

Keywords: 2D-MOF nanosheets; Electrochemical impedance spectroscopy; FRET; G-quadruplex; Lead ion.