title: Label-free electrochemical DNA sensor based on functionalised conducting copolymer.
abstract: A simple and label-free electrochemical sensor for recognition of the DNA hybridization event was prepared based on a new functionalised conducting copolymer, poly[pyrrole-co-4-(3-pyrrolyl) butanoic acid]. This precursor copolymer can be easily electrodeposited on the electrode surface and shows high electroactivity in an aqueous medium. An amino-substituted oligonucleotide (ODN) probe was covalently grafted onto the surface of the copolymer in a one step procedure and tested on hybridization with complementary ODN segments. The cyclic voltammogram of ODN probe-modified copolymer showed very little change when incubated in presence of non-complementary ODN, while a significant, and reproducible, modification of the voltammogram was observed after addition of complementary ODN. The AC impedance spectrum showed an increased charge transfer resistance (Rct) and double layer capacitance of the sensor film after hybridisation. Sensors with thinner films showed higher sensitivity than thicker films, suggesting that hybridisation at or near the surface of the film produces a larger change in electrical properties than that within the body of the film.
authors.affiliation: Polymer Electronics Research Centre, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.forename: Christian
authors.initials: C
authors.lastname: Soeller
authors.forename: Nickolas
authors.initials: N
authors.lastname: Vigar
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kilmartin
authors.forename: Mark B
authors.initials: MB
authors.lastname: Cannell
authors.forename: Graham A
authors.initials: GA
authors.lastname: Bowmaker
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Cooney
authors.forename: Jadranka
authors.initials: J
authors.lastname: Travas-Sejdic
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D020148:Butyric Acid / Q000737:chemistry*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D017403:In Situ Hybridization / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation / Q000379:methods*; D009841:Oligonucleotides / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D013194:Staining and Labeling
chemical_list: D009841:Oligonucleotides; D020148:Butyric Acid