Figure 4.

(A) Modular design of the electrochemical platform for the detection of three different clinically relevant antibodies: (B) cetuximab, (C) anti-HIV, and (D) anti-HA antibodies. Shown are (left) the SWV voltammograms recorded in the absence (blank) and presence (colored) of the target antibody, (center) the dose–response curves, and (right) the signal gain values obtained with the specificity tests. The experiments were performed in a 100 μL solution containing 90% bovine serum and 10% phosphate buffer (500 mM Na₂HPO₄ and 1.5 M NaCl at pH 7.0). Each solution also contains the pre-hybridized DNA duplex (60 nM), the scaffold DNA strands (60 nM each), and the peptide-PNA chimera (120 nM) and cetuximab/anti-HIV/anti-HA antibodies. Both the SWV examples and the specificity tests were performed at saturating concentrations of the target antibody (300 nM). The same experimental procedure described in Figure 3 was employed.