Figure 2.
Employing a pair of signalling probes differing in affinity we can broaden the dynamic range of E-DNA sensors. (A) We did so by co-immobilizing (1:1 ratio) on a single electrode surface a relatively low affinity E-DNA probe (e.g., probe 3GC, Kd = 580 nM) with a higher affinity E-DNA probe (e.g., probe 0GC, Kd = 19 nM). (B) The useful dynamic range (defined as the fold-concentration change upon transition from 10% occupancy to 90% occupancy) of these individual probes spans an 81-fold range of target concentrations over two distinct concentration regimes. (C) With this strategy the resulting dose-response curve is extended and spans a 1,000-fold range of target concentrations.