Fig. 2. Schematic representations of typical 2D electrode configurations and surface structures used in electrochemical biosensors: (a) a gold (Au) electrode with self-assembled monolayers (SAMs) facilitating biomolecule immobilization, (b) an indium tin oxide (ITO) electrode offering transparent conductivity for combined optical–electrochemical applications, (c) a boron-doped diamond (BDD) electrode characterized by a wide potential window, low background current, and superior chemical stability, and (d) a reduced graphene oxide (rGO) electrode featuring a large surface area and abundant functional groups to promote electron transfer and enhance probe immobilization. These illustrations emphasize the structural and functional characteristics of each electrode type described in Section 4.1.
