A nucleic acid dye-enhanced electrochemical biosensor for the label-free detection of Hg2+ based on a gold nanoparticle-modified disposable screen-printed electrode. Issue 35 (24th August 2022)

• Record Type: Journal Article
• Authors: Liu, Wei; Wang, Yunqi; Sheng, Fangfang; Wan, Bing; Tang, Gangxu; Xu, Shuxia
• Is Part Of: Analytical methods. Volume 14:Issue 35(2022)
• Page Start: 3451
• Page End: 3457
• Publication Date: 2022-08-24
• Subjects: Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; Chemical laboratories -- Standards -- Periodicals; 543.1905
• DOI: 10.1039/d2ay00548d
• Languages: English
• ISSNs: 1759-9660

Abstract

Abstract : A nucleic acid dye-enhanced electrochemical sensor was designed based on an Au nanoparticle (AuNPs)-modified screen-printed carbon electrode (SPCE) and a thymine (T)–Hg 2+ –thymine (T) mismatch for the detection of Hg 2+ in water. Abstract : In this paper, a nucleic acid dye-enhanced electrochemical biosensor based on a screen-printed carbon electrode (SPCE) modified with Au nanoparticles (AuNPs) was designed for the detection of Hg 2+ in water. AuNPs were modified on the surface of the disposable SPCE through the electrodeposition of HAuCl4 . Subsequently, thiolated DNA probes were immobilized on the AuNP-modified electrode surface by Au–S reaction. After Hg 2+ was bound with a DNA probe by thymine (T)–Hg 2+ –thymine (T) mismatch, the DNA probe was folded into a hairpin structure where positively charged GelRed molecules were embedded into the double-stranded part of the hairpin. Thus, the current of [Fe(CN)6 ] 3−/4− increased significantly on account of the decreased electrostatic repulsion at the electrode surface. Under the optimized experimental conditions, the peak current of [Fe(CN)6 ] 3−/4− exhibited a good linear relationship with lgCHg 2+ in the concentration of Hg 2+ linear range of 0.1 nM to 500 nM, and the limit of detection (S/N = 3) was calculated as 0.04 nM. The electrochemical sensor also exhibited excellent selectivity for Hg 2+ in the presence of nine interfering ions, including Na +, Fe 3+, Ni 2+, Mg 2+, Co 2+, Pb 2+, K +, Al 3+ and Cu 2+ . Meanwhile, the developed electrochemical sensor was tested in the analysis of Hg 2+ in tap water and river water samples, and the recoveries ranged from 81.0 to 114%. Therefore, this nucleic acid dye-enhanced electrochemical biosensor provided the advantages of simplicity, sensitivity, and specificity and is expected to be an alternative for Hg 2+ detection in actual environmental samples.