title: Switchable DNA interfaces for the highly sensitive detection of label-free DNA targets.
abstract: We report a method to detect label-free oligonucleotide targets. The conformation of surface-tethered probe nucleic acids is modulated by alternating electric fields, which cause the molecules to extend away from or fold onto the biased surface. Binding (hybridization) of targets to the single-stranded probes results in a pronounced enhancement of the layer-height modulation amplitude, monitored optically in real time. The method features an exceptional detection limit of <3 x 10(8) bound targets per cm(2) sensor area. Single base-pair mismatches in the sequences of DNA complements may readily be identified; moreover, binding kinetics and binding affinities can be determined with high accuracy. When driving the DNA to oscillate at frequencies in the kHz regime, distinct switching kinetics are revealed for single- and double-stranded DNA. Molecular dynamics are used to identify the binding state of molecules according to their characteristic kinetic fingerprints by using a chip-compatible detection format.
authors.affiliation: Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany. rant@wsi.tum.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Rant
authors.forename: Kenji
authors.initials: K
authors.lastname: Arinaga
authors.forename: Simon
authors.initials: S
authors.lastname: Scherer
authors.forename: Erika
authors.initials: E
authors.lastname: Pringsheim
authors.forename: Shozo
authors.initials: S
authors.lastname: Fujita
authors.forename: Naoki
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Marc
authors.initials: M
authors.lastname: Tornow
authors.forename: Gerhard
authors.initials: G
authors.lastname: Abstreiter
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D012680:Sensitivity and Specificity; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D006046:Gold; D004247:DNA