Single gene differentiation by DNA-modified carbon electrodes using an AC impedimetric approach.
A simple and novel electrochemical biosensor is described for differentiating between differing gene sequences on the basis of DNA hybridization events. Polyethylenimine-modified screen-printed carbon electrodes were used to immobilize single-stranded PCR fragments from plasmid DNA from the gene for pyruvate kinase. AC impedimetric measurements were first performed on these systems in buffer and then upon exposure to single-stranded DNA. When the electrode and solution DNA were complementary, a large drop in impedance was measured. Complementary DNA could be clearly detected at concentrations down to 1 fg/mL. Higher concentrations gave faster hybridization with saturation occurring at levels above 1 ng/mL. Responses were much lower upon exposure to noncomplementary DNA, even at higher concentrations, with the sensor showing a high degree of selectivity. This sensor format offers great promise for many DNA hybridization applications and lends itself to mass fabrication.
Davis
Frank
F
Cranfield Health, Cranfield University, Silsoe MK45 4DT, United Kingdom.
Hughes
Margaret A
MA
Cossins
Andrew R
AR
Higson
Séamus P J
SP
D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011770:Pyruvate Kinase / Q000235:genetics
D011770:Pyruvate Kinase