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A label-free electrochemical magnetic aptasensor based on exonuclease III–assisted signal amplification for determination of carcinoembryonic antigen.
- Source :
-
Microchimica Acta . Sep2020, Vol. 187 Issue 9, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
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Abstract
- A novel label-free and exonuclease III (Exo III)–assisted signal amplification electrochemical aptasensor was constructed for the determination of carcinoembryonic antigen (CEA) via magnetic field–induced self-assembly of magnetic biocomposites (Fe3O4@Au NPs-S1-S2-S3). The magnetic biocomposites were acquired by modifying double-stranded DNA (S1-S2-S3) on the surface of Fe3O4@Au nanoparticles (Fe3O4@Au NPs). Among them, Fe3O4@Au NPs were used as carriers for magnetic separation, thiolated single-stranded DNA (S1) provided signal sequence, CEA aptamer (S2) worked as a recognition element, and complementary strand (S3) was used to form double strands. In the presence of CEA, S2 bonded with CEA competitively; the exposed S1 could not be cleaved since Exo III was inactive against ssDNA. The G-quadruplex/hemin complexes finally formed with the existence of K+, and the high electrochemical signal of G-quadruplex/hemin complexes was recorded by differential pulse voltammetry (DPV) at − 0.6 V. Conversely, in the absence of CEA, dsDNA was cleaved from the 3′ blunt end by Exo III; the disappearance of G-rich sequence blocked the generation of the signal. This method exhibited good selectivity and sensitivity for the determination of CEA; the linear range was from 0.1 to 200 ng mL−1 and the limit of detection was 0.4 pg mL−1. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00263672
- Volume :
- 187
- Issue :
- 9
- Database :
- Academic Search Index
- Journal :
- Microchimica Acta
- Publication Type :
- Academic Journal
- Accession number :
- 145975821
- Full Text :
- https://doi.org/10.1007/s00604-020-04457-7