Fig. 6
Impedance responses during hybridization of probe-DNA attached to VASWCNTs on the gold surface. Time-dependent impedance response of probe-DNA attached to SWCNTs on the gold surface in 1 mM [Fe(CN)6]3−/4− + 0.1 M aqueous KCl with a 300 nM cDNA and b 300 nM nCDNA, and c variation of charge-transfer resistance (R ct) against time for cDNA (black squares) and nCDNA (black circles). A downward arrow in a indicated decrease of R ct (diameter of semicircles) with time. Solid lines are the fit to the experimental response using an appropriate equivalent circuit, which is shown as an inset of Fig. 4 a