title: Electrochemical detection of DNA hybridization amplified by nanoparticles.
abstract: Detection of specific oligonucleotide (ODN) fragments has become an important field in many areas of biomedicine. We describe a novel ODN sensor based on electropolymerization of a conducting polymer (polypyrrole) in the presence of a sample containing ODN(s). The resulting trapped ODN(s) are then probed by addition of complimentary sequence ODN. By incorporating CdS nanoparticles with the probe, a significant improvement in sensor sensitivity was observed. Impedance spectroscopy suggested that optimal detection of hybridization occurred at frequencies>or=3000 Hz (for a 0.07 cm2 85 nm thick film). At these frequencies, the impedance signal was almost linear with the logarithm of ODN concentration in the range 3.7-370 nM with a detection limit of approximately 1 nM ODN (for the sensor fabricated). Importantly, the sensor could be regenerated by removing hybridized ODN with NaOH suggesting possibility of the sensor re-use.
authors.affiliation: Polymer Electronics Research Centre, The University of Auckland, 23 Symonds Street, Private Bag 92019, Auckland 1001, New Zealand.
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.forename: Christian
authors.initials: C
authors.lastname: Soeller
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 / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000235:genetics; D017097:Electric Impedance; D020869:Gene Expression Profiling / Q000379:methods*; D017403:In Situ Hybridization / Q000379:methods*; D009155:Mutism; D049329:Nanostructures / Q000737:chemistry*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*
chemical_list: D004247:DNA