title: Label-free potentiometry for detecting DNA hybridization using peptide nucleic acid and DNA probes.
abstract: Peptide nucleic acid (PNA) has outstanding affinity over DNA for complementary nucleic acid sequences by forming a PNA-DNA heterodimer upon hybridization via Watson-Crick base-pairing. To verify whether PNA probes on an electrode surface enhance sensitivity for potentiometric DNA detection or not, we conducted a comparative study on the hybridization of PNA and DNA probes on the surface of a 10-channel gold electrodes microarray. Changes in the charge density as a result of hybridization at the solution/electrode interface on the self-assembled monolayer (SAM)-formed microelectrodes were directly transformed into potentiometric signals using a high input impedance electrometer. The charge readout allows label-free, reagent-less, and multi-parallel detection of target oligonucleotides without any optical assistance. The differences in the probe lengths between 15- to 22-mer dramatically influenced on the sensitivity of the PNA and DNA sensors. Molecular type of the capturing probe did not affect the degree of potential shift. Theoretical model for charged rod-like duplex using the Gouy-Chapman equation indicates the dominant effect of electrostatic attractive forces between anionic DNA and underlying electrode at the electrolyte/electrode interface in the potentiometry.
authors: Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda, Tokyo, Japan. goda.bsr@tmd.ac.jp
authors: Tatsuro
authors: T
authors: Goda
authors: Ankit Balram
authors: AB
authors: Singi
authors: Yasuhiro
authors: Y
authors: Maeda
authors: Akira
authors: A
authors: Matsumoto
authors: Masaki
authors: M
authors: Torimura
authors: Hiroshi
authors: H
authors: Aoki
authors: Yuji
authors: Y
authors: Miyahara
mesh_terms: D004247:DNA / Q000378:metabolism*; D015342:DNA Probes / Q000378:metabolism*; D004566:Electrodes; D009693:Nucleic Acid Hybridization; D020135:Peptide Nucleic Acids / Q000378:metabolism*; D011199:Potentiometry / Q000379:methods*; D013194:Staining and Labeling; D055672:Static Electricity; D013997:Time Factors
chemical_list: D015342:DNA Probes; D020135:Peptide Nucleic Acids; D004247:DNA