Fig. 4.

Temperature dependence of the electrocatalysis of MB-DNA. The temperature was increased at a rate of 0.5 °C/ min by a Peltier device placed beneath the multiplexed chip. The electrocatalytic amplification was monitored by chronocoulometry at two-second intervals. Left: The accumulated charge is plotted as a function of the measured solution temperature. Two different linear regimes can be discerned with rates of 20 μC/°C and 60 μC/°C at moderate (24–32 °C) and high (32–40 °C) temperatures, respectively. Right: In each regime, the effect on mismatch discrimination was examined by chronocoulometry; well-matched (blue) and mismatched (red) MB-DNA are shown at both 25 °C (Bottom) and 38 °C (Top). All scans were acquired in phosphate buffer (5 mM phosphate, 5 mM NaCl, 40 mM MgCl₂, 5 mM spermidine, and pH 7).