Fig. 6.

Electrochemical proteins detected in serum by multi-electrode array integrated into microfluidic system featuring a capture and a detection channel made from PDMS encased in polymethylmethacrylate plastic (A). The electrochemical sensor array was positioned in a PDMS microfluidic channel containing a platinum (Pt) wire as the counter electrode and a silver/silver chloride (Ag/ AgCl) wire reference electrode. Amperometry signal was generated upon incubation with Ab₂-MB-HRP-analytes in the measurement chamber for 20 min, then injecting a mixture of H₂O₂ and HQ: (B) duplicate responses in simultaneous array measurements on a standard mixture of 10 fg mL⁻¹ IL-6, 15 fg mL⁻¹ IL-8, 25 fg mL⁻¹ VEG, and 60 fg mL⁻¹ VEGFC illustrating reproducibility, (C) responses to human VEGF in mixtures of biomarker proteins (peaks for VEGF were extracted from four-protein determinations and presented together), (D–G) corresponding Array calibration plots of standard mixtures in calf serum for IL-6 (D), IL-8 (E), VEGF (F), VEGF-C (G). Standard deviations correspond to 2 sensors each on three separate arrays (n = 6). Adapted from ref. 88. Copyright 2012 American Chemical Society.