Figure 10.

(A) Covalent attachment of 3-aminopropyltriethoxysilane (APTES) to a hydroxyl-terminated graphene surface; (B) Resistance across a 100 μm × 4 mm graphene channel as a function of the hCG concentration. Resistance across the channel as a function of the urea and cortisol concentration (inset, top left). I–V curves are plotted (inset, bottom right) for the unmodified device (black curve), amine-terminated (red curve), and Ab-modified (blue curve) graphene surface. Reprinted from [59], Copyright 2014, with permission from Elsevier. (C) Sandwich-type electrochemical immunosensor based of Fc-modified Cu₂ONPs, for PSA detection. (D) SWVs for detection of 0.05 pg mL⁻¹ (a), 0.1 pg mL⁻¹ (b), 0.5 pg mL⁻¹ (c), 1 pg mL⁻¹ (d), 5 pg mL⁻¹ (e), 10 pg mL⁻¹ (f), 50 pg mL⁻¹ (g) and 100 pg mL⁻¹ (h) PSA. Reprinted from [62], Copyright 2016, with permission from Elsevier.