DNA Electrochemical Sensor Based on Conducting Polymer: Dependence of the 'Signal-On' Detection on the Probe Sequence Localization

摘要

We show in this work that it is possible to make selective direct electrochemical hybridization detection of a target strand onto a probe strand immobilized on a conducting polymer modaified with a quinone group, which presentscanon-exchange properties. This leads to a "signal-on" detection, a unique behavior in comparison to similarsystems described in the literature. It is shown that this systsm is efficient for various probe and target lengths(10-30 bp) and can discriminate a single mismatch. To go further in comprehension of the detection mechanism,a systematic study of the electrochemical response versus the probe sequence localization onto the immobilizedstrand is performed. For example, a 30-bp target strand is divided into three shorter 10-bp sequences (A-C,respectively), and we inVestigate the successive hybridrzation of these 1/3 strands ontO the 30-bp probe strand. Itis shown that one probe strand can be used to address several shorter targets.