title: A Multiplexed, Two-Electrode Platform for Biosensing Based on DNA-Mediated Charge Transport.
abstract: We have developed a thin layer, multiplexed biosensing platform that features two working-electrode arrays for detecting small molecules, nucleic acid sequences, and DNA-binding proteins. DNA duplexes are patterned onto the primary electrode array, while a secondary electrode array is used both to initiate DNA monolayer formation and for electrochemical readout via DNA-mediated charge transport (DNA CT) chemistry. Electrochemical reduction of Cu(phendione)2(2+) (phendione is 1,10-phenanthroline-5,6-dione) at the secondary electrodes induces covalent attachment via click chemistry of ethynyl-labeled DNA probe duplexes onto the primary electrodes that have been treated with azide-terminated alkylthiols. Electrochemical impedance spectroscopy and cyclic voltammetry confirm that catalyst activation at the secondary electrode is essential to maintain the integrity of the DNA monolayer. Electrochemical readout of DNA CT processes that occur at the primary electrode is accomplished also at the secondary electrode. The two-electrode system enables the platform to function as a collector-generator using either ferrocyanide or ferricyanide as mediators with methylene blue and DNA charge transport. Electrochemical measurements at the secondary electrode eliminate the need for large background corrections. The resulting sensitivity of this platform enables the reliable and simultaneous detection of femtomoles of the transcription factors TATA-binding protein and CopG on a single multiplexed device.
authors.affiliation: †Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
authors.forename: Ariel L
authors.initials: AL
authors.lastname: Furst
authors.affiliation: †Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.|‡Department of Chemistry and Chemical Biology, Occidental College, Los Angeles, California 90041, United States.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hill
authors.affiliation: †Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Barton
mesh_terms: D001386:Azides / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D002384:Catalysis; D057930:Click Chemistry; D004247:DNA / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000032:analysis*; D055664:Electrochemical Techniques; D004566:Electrodes; D010618:Phenanthrolines / Q000737:chemistry
chemical_list: D001386:Azides; D015342:DNA Probes; D004268:DNA-Binding Proteins; D010618:Phenanthrolines; C037153:1,10-phenanthroline-5,6-dione; D004247:DNA