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Potentiometric aptasensing of Escherichia coli based on electrogenerated chemiluminescence as a highly sensitive readout

We introduce here a versatile approach to read out potentiometric aptasensors by electrogenerated chemiluminescence (ECL), which can amplify the small potential changes induced by the bacterial concentrations via ECL signals. In the present system, the electrode modified with single-walled carbon na...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2022-03, Vol.200, p.113923-113923, Article 113923
Main Authors: Gao, Xueqing, Jiang, Tianjia, Qin, Wei
Format: Article
Language:English
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Summary:We introduce here a versatile approach to read out potentiometric aptasensors by electrogenerated chemiluminescence (ECL), which can amplify the small potential changes induced by the bacterial concentrations via ECL signals. In the present system, the electrode modified with single-walled carbon nanotubes (SWCNTs) and aptamer molecules acts as the reference electrode and is placed in the sample solution for sensing the bacterial concentration changes, while the Ru(bpy)32+ modified gold electrode serves as the working electrode for generating ECL signals and is placed in the detection solution containing tripropylamine (TPA) spatially separated from the sample solution by a salt bridge. Ru(bpy)32+ is immobilized on the gold electrode's surface for enhancement of luminous efficiency and reduction of reagent consumption. A moving-part-free fluid flowing system is introduced to promote the mass transport of TPA from the detection solution to the surface of the ECL generating electrode. When a constant potential is imposed between the working and reference electrodes, the potential changes at the SWCNTs-aptamer modified electrode induced by the bacterial concentrations can modulate the potentials at the Ru(bpy)32+ modified electrode, thus generating the ECL signals. The developed sensing strategy shows a highly sensitive response to E. coli O157: H7 in the linear range of 5–1000 CFU mL−1 with a low detection limit of 2 CFU mL−1. We believe that the proposed approach is promising to develop aptasensors for sensitive detection of bacterial cells. [Display omitted] •A sensitive approach is proposed to detect Escherichia coli based on the potential-modulated ECL signals.•The Ru(bpy)32+ immobilized electrode is used for enhancement of luminous efficiency and reduction of reagent consumption.•A moving-part-free fluid flowing system is introduced to promote the mass transports of the ECL reactant.•The ECL readout mode can provide the greatly improved sensitivity and accuracy for potentiometric aptasensor.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2021.113923