Fig. 3.

Lateral view scheme of an impedimetric genosensor based on Si nanowire array/PNA. (a) Neutral PNA molecules are grafted on the surface of Si nanowires by single-point attachment. (b) After specific hybridization with the negatively charged complementary single-stranded denatured RT-PCR product of dengue virus genome amplification, accumulation of negative charges (solely derived from the dengue amplicon) near the conducting Si nanowire surface leads to an increase in electrical resistance between the electrodes.