Electrochemical detection of DNA hybridization amplified by nanoparticles.
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.
Peng
Hui
H
Polymer Electronics Research Centre, The University of Auckland, 23 Symonds Street, Private Bag 92019, Auckland 1001, New Zealand.
Soeller
Christian
C
Cannell
Mark B
MB
Bowmaker
Graham A
GA
Cooney
Ralph P
RP
Travas-Sejdic
Jadranka
J
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*
D004247:DNA