Multifunctional Electrode Arrays: Towards a Universal Detection Platform

In this article we review recent work in our laboratory towards the realization of a multianalyte microelectrode detection platform capable of discriminating chemicals and different biomolecules simultaneously. The functionalization of electrodes with aryl diazonium salts provides an electrically addressable deposition procedure capable of immobilizing a wide range of molecules. We demonstrate control over surface density and electron transfer kinetics as well as the activation of individual electrodes in an array. The direct electrically‐addressable immobilization of diazonium‐modified proteins is shown to be suitable for the construction of multianalyte immunosensors and the immobilization of horseradish peroxidase leading to the direct electron transfer between the redox enzyme and the electrode. The use of catalytic nanoparticles leads to the construction of a reagent‐less immunosensor and the simultaneous detection of DNA and proteins on the same electrode array is demonstrated.