Effect of Electrochemically Grafted Aryl-Based Monolayer on Nonspecific Electrical Signal of Field-Effect-Transistor-Based Biosensor

In this study, we demonstrate the use of a monolayer film electrografted via diazonium chemistry for controlling the potential response of field-effect transistor (FET)-based sensor. A 4-nitrobenzenediazonium salt is electrografted on an extended-Au-gate FET (EG-Au-FET) with using a radical scavenger by cyclic voltammetry (CV), resulting in the formation of a monolayer. In particular, the surface coverage of the aryl-derivative monolayer on the Au gate electrode gradually increases with increasing number of potential cycles in CV. That is, the denser the surface coverage of the grafted monolayer, the smaller the potential response of the EG-Au-FET. Thus, a platform based on such a monolayer film electrografted via diazonium chemistry is suitable for controlling the potential response based on the interference of low-molecular-weight biomolecules in biosamples.