Electrically addressable diazonium-functionalized antibodies for multianalyte electrochemical sensor applications

The direct electrically addressable deposition of diazonium-modified antibodies is examined for electrochemical immunosensing applications. The immobilized antibodies can be detected by the use of electroactive enzyme tags and nanoparticle-gold labeling. Control over antibody functionalization density and minimal spontaneous grafting of diazonium–antibody adducts is shown. The utility of the technique for a sandwich immunoassay as well as the ability to individually and selectively address closely spaced microelectrodes for multi-target protein detection in an array format is demonstrated.