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Biosens Bioelectron. 2014 Apr 15;54:415-20. doi: 10.1016/j.bios.2013.11.036. Epub 2013 Nov 18.

A pseudo triple-enzyme cascade amplified aptasensor for thrombin detection based on hemin/G-quadruplex as signal label.

Author information

1
Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, The Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Chongqing 400715, PR China.
2
Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, The Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Chongqing 400715, PR China. Electronic address: xwju@swu.edu.cn.

Abstract

In this work, a pseudo triple-enzyme cascade amplified electrochemical aptasensor based on hemin/G-quadruplex as signal label for thrombin (TB) was constructed and the amplified electrochemical signal was achieved by the corporate catalysis of alcohol dehydrogenase-graphene sheets (ADH-GSs) bionanocomposite and hemin/G-quadruplex, which simultaneously acted as NADH oxidase and HRP-mimicking DNAzyme. Through "sandwich" reaction, hemin/G-quadruplex labeled gold nanoparticles-ADH-GSs bionanocomposite (AuNPs-ADH-GSs) was captured on electrode surface and thus obtained the electrochemical signal. After the addition of ethanol into the electrolytic cell, ADH availably catalyzed the oxidation of ethanol with the reduction of NAD(+) to NADH. Then, hemin/G-quadruplex as NADH oxidase catalyzed the oxidization of NADH, accompanying with the production of H2O2. Simultaneously, hemin/G-quadruplex as HRP-mimicking DNAzyme catalyzed the reduction of the generated H2O2. Such a catalysis strategy greatly promoted the electron transfer of hemin and resulted in the specific enhancement of electrochemical signal. The proposed TB aptasensor achieved a linear range of 1 pM-50 nM with a detection limit of 0.3 pM (defined as S/N=3). In addition, it showed satisfying stability and reproducibility, good specificity and sensitivity, indicating promising application for the detection of various proteins in clinical analysis.

KEYWORDS:

Alcohol dehydrogenase-graphene; Aptasensor; Hemin/G-quadruplex; Pseudo triple-enzyme; Thrombin

PMID:
24296062
DOI:
10.1016/j.bios.2013.11.036
[Indexed for MEDLINE]

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