Aβ-specific MIE. (A) Schematic of MIE. Anti-Aβ antibodies are covalently attached to the electrode surface, and then unbound space is blocked with BSA. An electrode held at 0.65 V induces oxidation of Tyr amino acids. Oxidation releases an electron that the carbon fiber detects as current. The amount of current is proportional to the amount of Tyr present. Because many proteins in the extracellular space contain Tyr residues, the inclusion of an anti-Aβ antibody is a necessary factor that determines specificity of the electrode. (B) Peak oxidation current of Aβ MIE in matched concentrations of human and mouse Aβ (n = 3; mean ± SEM).