title: Electronic detection of nucleic acids: a versatile platform for molecular diagnostics.
abstract: A novel platform for the electronic detection of nucleic acids on microarrays is introduced and shown to perform well as a selective detection system for applications in molecular diagnostics. A gold electrode in a printed circuit board is coated with a self-assembled monolayer (SAM) containing DNA capture probes. Unlabeled nucleic acid targets are immobilized on the surface of the SAM through sequence-specific hybridization with the DNA capture probe. A separate signaling probe, containing ferrocene-modified nucleotides and complementary to the target in the region adjoining the capture probe binding site, is held in close proximity to the SAM in a sandwich complex. The SAM allows electron transfer between the immobilized ferrocenes and the gold, while insulating the electrode from soluble redox species, including unbound signaling probes. Here, we demonstrate sequence-specific detection of amplicons after simple dilution of the reaction product into hybridization buffer. In addition, single nucleotide polymorphism discrimination is shown. A genotyping chip for the C282Y single nucleotide polymorphism associated with hereditary hemochromatosis is used to confirm the genotype of six patients' DNA. In addition, a gene expression-monitoring chip is described that surveys five genes that are differentially regulated in the cellular apoptosis response. Finally, custom modification of individual electrodes through sequence-specific hybridization demonstrates the potential of this system for infectious disease diagnostics. The versatility of the electronic detection platform makes it suitable for multiple applications in diagnostics and pharmacogenetics.
authors.affiliation: Clinical Micro Sensors Division of Motorola, Inc., Pasadena, California 91105, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Umek
authors.forename: S W
authors.initials: SW
authors.lastname: Lin
authors.forename: J
authors.initials: J
authors.lastname: Vielmetter
authors.forename: R H
authors.initials: RH
authors.lastname: Terbrueggen
authors.forename: B
authors.initials: B
authors.lastname: Irvine
authors.forename: C J
authors.initials: CJ
authors.lastname: Yu
authors.forename: J F
authors.initials: JF
authors.lastname: Kayyem
authors.forename: H
authors.initials: H
authors.lastname: Yowanto
authors.forename: G F
authors.initials: GF
authors.lastname: Blackburn
authors.forename: D H
authors.initials: DH
authors.lastname: Farkas
authors.forename: Y P
authors.initials: YP
authors.lastname: Chen
mesh_terms: D017209:Apoptosis; D020137:Base Pair Mismatch; D001483:Base Sequence; D018076:DNA, Complementary / Q000378:metabolism; D004563:Electrochemistry; D005838:Genotype; D006046:Gold; D008969:Molecular Sequence Data; D009696:Nucleic Acids / Q000737:chemistry* / Q000648:ultrastructure*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation* / Q000379:methods*; D020641:Polymorphism, Single Nucleotide; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature
chemical_list: D018076:DNA, Complementary; D009696:Nucleic Acids; D006046:Gold; D012194:RNA-Directed DNA Polymerase