Figure 4.

(A) EIS of the boronate-covered electrodes before (curve a) and after incubation with Au NPs (curve b), BDBA (curve c) or the mixture of Au NPs and BDBA (curve d). Curve e corresponds to that of the H₂O₂-treated boronate-covered electrode after incubation with the mixture of Au NPs and BDBA. The final concentrations of Au NPs, BDBA and H₂O₂ used were 2 nM, 10 µM and 10 µM, respectively; (B) Effect of [peptide]/[Au NPs] ratio on R_et; (C) Dependence of ΔR_et on H₂O₂ concentration (0.001, 0.01, 0.06, 0.1, 0.6, 3, 10 and 30 µM). The inset shows the linear part of the curve. The concentrations of Au NPs and BDBA used were 2 and 9 µM, respectively.