earticle

영어

The signal amplification technique of PNA-based electrochemical DNA sensor was developed utilizing enzymatic catalysis. Electrochemical detection of DNA hybridization on a PNA-modified electrode is based on the change of surface charge caused by the hybridization of negatively charged DNA molecules. Negatively charged mediator, ferrocenedicarboxylic acid, can not diffuse to the DNA hybridized electrode surface due to the charge repulsion with the hybridized DNA molecule while it can easily approach the neutral PNA-modified electrode surface without the hybridization. By employing glucose oxidase catalysis on this PNA-based electrochemical system, the oxidized mediator could be immediately reduced leading to greatly increased electrochemical signals. Using the enzymatic strategy, we successfully demonstrated its clinical utility by detecting one of the mutation sequences of breast cancer susceptibility gene BRCA1 at the sample concentration lower than 10-9 M. Furthermore, a single base-mismatched sample could be also discriminated from a perfectly matched sample.