High performance NiO_x extended-gate field-effect transistor biosensor for detection of uric acid

In this paper, we developed a high performance NiO_x extended-gate field-effect transistor (EGFET) biosensor for detection of uric acid. The structural and sensing properties of the NiO_x sensing film deposited on a n⁺-type Si substrate was examined for an EGFET pH sensor. X-ray diffraction, atomic force microscope and X-ray photoelectron spectroscopy were used to analyze the film features of the NiO_x sensing film. The NiO_x sensing film based on EGFET exhibited a high pH sensitivity of 58.53 mV pH⁻¹, a small hysteresis voltage of 1.4 mV and a low drift rate of 0.30 mV h⁻¹. Moreover, the NiO_x EGFET biosensor showed a high linearity in the uric acid range between 1 and 30 mg dl⁻¹. In addition, this NiO_x EGFET biosensor demonstrated a very good selectivity to uric acid over other interfering substrates (ascorbic acid, glucose, urea).