title: Redox cycling amplified electrochemical detection of DNA hybridization: application to pathogen E. coli bacterial RNA.
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).
authors.affiliation: Department of Nanoengineering, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Walter
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Gerd-Uwe
authors.initials: GU
authors.lastname: Flechsig
authors.forename: David A
authors.initials: DA
authors.lastname: Haake
authors.forename: Joseph
authors.initials: J
authors.lastname: Wang
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D000627:Aminophenols / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D004247:DNA / Q000032:analysis / Q000737:chemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry; D007097:Imines / Q000737:chemistry; D057230:Limit of Detection; D009243:NAD / Q000737:chemistry*; D009693:Nucleic Acid Hybridization / Q000379:methods; D010084:Oxidation-Reduction; D012329:RNA, Bacterial / Q000032:analysis*; D019809:Streptavidin / Q000737:chemistry; D013457:Sulfur Compounds / Q000737:chemistry
chemical_list: D000627:Aminophenols; D016227:Benzoquinones; D004800:Enzymes, Immobilized; D007097:Imines; D012329:RNA, Bacterial; D013457:Sulfur Compounds; D009243:NAD; C064299:1,4-benzoquinoneimine; D001710:Biotin; D006046:Gold; D004247:DNA; D019809:Streptavidin; D000469:Alkaline Phosphatase; C026729:4-aminophenol