Fig. 1. The E-DNA scaffold sensor supports the single-step measurement of the concentration of specific antibodies.

a In the absence of the targeted antibody, the DNA scaffold efficiently transfers electrons to the gold electrode. Upon antibody binding, in contrast, steric hindrance reduces electron transfer. b The resultant change in electron transfer rate is easily detected using square wave voltammetry. As shown, for example, the addition of 10 nM of the target antibody (here an anti-FLAG antibody) produces a 30% decrease in the signaling current.