title: Cantilever-based optical deflection assay for discrimination of DNA single-nucleotide mismatches.
abstract: Characterization of single-nucleotide polymorphisms is a major focus of current genomics research. We demonstrate the discrimination of DNA mismatches using an elegantly simple microcantilever-based optical deflection assay, without the need for external labeling. Gold-coated silicon AFM cantilevers were functionalized with thiolated 20- or 25-mer probe DNA oligonucleotides and exposed to target oligonucleotides of varying sequence in static and flow conditions. Hybridization of 10-mer complementary target oligonucleotides resulted in net positive deflection, while hybridization with targets containing one or two internal mismatches resulted in net negative deflection. Mismatched targets produced a stable and measurable signal when only a four-base pair stretch was complementary to the probe sequence. This technique is readily adaptable to a high-throughput array format and provides a distinct positive/negative signal for easy interpretation of oligonucleotide hybridization.
authors.affiliation: Life Sciences Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Hansen
authors.forename: H F
authors.initials: HF
authors.lastname: Ji
authors.forename: G
authors.initials: G
authors.lastname: Wu
authors.forename: R
authors.initials: R
authors.lastname: Datar
authors.forename: R
authors.initials: R
authors.lastname: Cote
authors.forename: A
authors.initials: A
authors.lastname: Majumdar
authors.forename: T
authors.initials: T
authors.lastname: Thundat
mesh_terms: D020137:Base Pair Mismatch; D004247:DNA / Q000302:isolation & purification*; D009693:Nucleic Acid Hybridization; D020641:Polymorphism, Single Nucleotide; D012825:Silicon
chemical_list: D004247:DNA; D012825:Silicon