Potentiometric biosensors

Potentiometric biosensors apply an electrochemical cell with two reference electrodes, largely ion-selective electrodes (ISEs), to measure the accumulation of a charge at an electrode while drawing negligible current flow ^{[109], [110]}. For biological detection, enzymes are usually employed in the potentiometric sensors to catalyze chemical reaction and produce ions in the vicinity of the sensing ISE ^{[111], [112]}. Potentiometric biosensors have several advantages of small size, rapid response, ease of use, low cost, resistant to color, turbid interferences, and is independent of the sample volume ^[113], making it promising for POC diagnostic applications. As a paradigm, Tarasov et al. developed a novel potentiometric biosensor based on extended-gate field-effect transistors in a dual-chip configuration for on-site serological diagnosis of Bovine Herpes Virus-1 (BHV-1) (Fig. 1C) ^[114]. The potentiometric biosensor was then demonstrated to be highly sensitive and selective to detect BHV-1 in real serum samples from cattle, which could be easily integrated to POC devices for the POC diagnosis of a wide range of human and animal diseases ^[114].