A homogeneous label-free electrochemical aptasensor based on an omega-like DNA nanostructure for progesterone detection

• Published in: Analytical methods Vol. 15; no. 45; pp. 6159 - 6164
• Main Authors: Wang, Zaofen, Shi, Weiping, Tan, Yunzhu, Liu, Bingqian
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 23.11.2023
• Subjects: Aptamers; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA structure; DNA, Catalytic - chemistry; Electrochemistry; Exonuclease; Hemin; Hydrogen Peroxide; Labels; Nanostructure; Nanostructures; o-Phenylenediamine; Oligonucleotides; Oxidation; Phenylenediamine; Progesterone; Strands
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/d3ay01255g

A novel homogeneous label-free electrochemical aptamer sensor for the detection of progesterone was prepared by combining a well-designed omega (Ω)-like DNA (Ω-DNA) nanostructure, with an isothermal cycling amplification strategy based on the highly efficient exonuclease III (Exo III). The omega-like (Ω) DNA is composed of two oligonucleotide strands: DNA 1 and DNA 2 . The Pro aptamer triggers a chain displacement reaction of Ω-DNA nanostructures, forms a new double-stranded DNA structure (aptamer precursor-DNA 2 ), and releases DNA 1 . Then, Exo III selectively cleaves the DNA duplex and releases the Pro aptamer to participate in a new displacement reaction. Meanwhile, the released DNA 1 strands gain access to the strongly bound hemin, forming a hemin/G-quadruplex (DNAzyme). In the presence of hydrogen peroxide (H 2 O 2 ), differential pulse voltammetry (DPV) was used to detect the current signal from the oxidation of o -phenylenediamine (OPD) to aminoazobenzene (DAP) catalyzed by DNAzyme. However, the amount of released DNA 1 from the Ω-DNA nanostructures is reduced in the presence of the target Pro, and the DPV signal declines because of the small amount of DNAzyme formed. The developed electrochemical aptasensor has a wide dynamic linear relationship in the range of 1 pg mL −1 to 10 ng mL −1 under optimal conditions. Its detection limit is down to 0.3 pg mL −1 , providing a potential platform for a sensitive Pro assay among electrochemical assays. A novel homogeneous label-free electrochemical aptamer sensor for the detection of progesterone was prepared by combining the omega-like DNA nanostructure, with an isothermal cycling amplification strategy based on the exonuclease III.