Effect of reference electrode in the nanoFET (field-effect transistor)-based biosensor experiment

The reference electrode in an electrolyte solution affects the surface potential of the nanoFET (field-effect transistor) channel which can result in a false signal to be measured in the FET channel during bio- and chemical sensing experiments. In this reported work, it was demonstrated that different sensing results that were obtained were affected by the choice of the reference electrode through a pH and ion concentration sensing experiment. Three types of reference electrodes were compared: the SCE (saturated calomel reference electrode), the Ag/AgCl tube and the integrated Ag/AgCl electrode. The pH sensitivity equivalent to the surface potential was evaluated: 32.3, 34.6 and 16.3 mV/pH in the case of the SCE, the refillable tube type Ag/AgCl and the integrated Ag/AgCl, respectively.