Redox cycling amplified electrochemical detection of DNA hybridization: application to pathogen E. coli bacterial RNA |
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| Authors: | Walter Anne Wu Jie Flechsig Gerd-Uwe Haake David A Wang Joseph |
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| Affiliation: | aDepartment of Nanoengineering, University of California San Diego, La Jolla, CA 92093, United States;bKey Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), Department of Chemistry, Nanjing University, Nanjing 210093, PR China;cUniversity of Rostock, Department of Chemistry, Dr.-Lorenz-Weg 1, D-18051 Rostock, Germany;dDepartment of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095, United States;eVeterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States |
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| Abstract: | An electrochemical genosensor in which signal amplification is achieved using p-aminophenol (p-AP) redox cycling by nicotinamide adenine dinucleotide (NADH) is presented. An immobilized thiolated capture probe is combined with a sandwich-type hybridization assay, using biotin as a tracer in the detection probe, and streptavidin-alkaline phosphatase as reporter enzyme. The phosphatase liberates the electrochemical mediator p-AP from its electrically inactive phosphate derivative. This generated p-AP is electrooxidized at an Au electrode modified self-assembled monolayer to p-quinone imine (p-QI). In the presence of NADH, p-QI is reduced back to p-AP, which can be re-oxidized on the electrode and produce amplified signal. A detection limit of 1 pM DNA target is offered by this simple one-electrode, one-enzyme format redox cycling strategy. The redox cycling design is applied successfully to the monitoring of the 16S rRNA of E. coli pathogenic bacteria, and provides a detection limit of 250 CFU μL−1. |
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| Keywords: | Electrochemistry Genosensor Amplification Redox cycling Escherichia coli |
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