Summary of the types of potentiometric biosensors, with an example schematic of each type: Ion-selective electrode for the detection of recombinant human myelin basic protein [9], a modified screen-printed electrode for the simultaneous detection of Hg2+, Cd2+, and As3+ [23], a graphene-based field effect transistor for the detection of neuropeptide Y [34], a self-powered biosensor for the detection of a single nucleotide polymorphism [38], and a flexible, fabric-based biosensor for the detection of glucose [32].