title: Reagentless, ratiometric electrochemical DNA sensors with improved robustness and reproducibility.
abstract: To make the electrochemical DNA sensors (E-sensor) more robust and reproducible, we have now for the first time adapted the techniques of ratiometric analyses to the field of E-sensors. We did this via the simple expedient way of simultaneously using two redox probes: Methylene blue as the reporter of the conformational change, and ferrocene as an internal control. During the conformational transduction, only the distance between the signal probe and the electrode surface undergoes an appreciable change, while the distance between the control probe and the electrode remains relatively constant. This special design has allowed very reliable target recognition, as illustrated in this report using a human T-lymphotropic virus type I gene fragment. The standard deviation between measurements obtained using different electrodes was an order of magnitude less than that obtained using a classic E-sensor, which we prepared as a control. A limit of detection of 25.1 pM was obtained with our new system, with a single mismatch discrimination factor of 2.33 likewise being observed. Additionally, this concept had general applicability, and preliminary data of a "Signal-On" ratiometric E-sensor are also provided. Taken in concert, these results serve to validate the utility of what we believe will emerge as an easily generalized approach to oligonucleotide recognition and sensing.
authors.affiliation: Institute for Cellular and Molecular Biology, Center for Systems and Synthetic Biology, and Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Du
authors.forename: Byung Joon
authors.initials: BJ
authors.lastname: Lim
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Yu Sherry
authors.initials: YS
authors.lastname: Jiang
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Sessler
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellington
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D015342:DNA Probes; D055664:Electrochemical Techniques / Q000295:instrumentation*; D005814:Genes, Viral; D015368:Human T-lymphotropic virus 1 / Q000235:genetics; D015203:Reproducibility of Results
chemical_list: D015342:DNA Probes; D004247:DNA