Electronic detection of nucleic acids: a versatile platform for molecular diagnostics.
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.
Umek
R M
RM
Clinical Micro Sensors Division of Motorola, Inc., Pasadena, California 91105, USA.
Lin
S W
SW
Vielmetter
J
J
Terbrueggen
R H
RH
Irvine
B
B
Yu
C J
CJ
Kayyem
J F
JF
Yowanto
H
H
Blackburn
G F
GF
Farkas
D H
DH
Chen
Y P
YP
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
D018076:DNA, Complementary; D009696:Nucleic Acids; D006046:Gold; D012194:RNA-Directed DNA Polymerase