Enhanced electron transfer properties of NiO thin film for the efficient detection of urea

Abstract

Ur/NiO matrix is used efficiently for the detection of Urea. NiO thin film is deposited using rf magnetron sputtering. Variation in processing pressure (10–40 mT) and growth temperature (room temperature to 500 °C) during film deposition alter its defect profile, thus tailoring the charge transfer characteristics. The studies reveal a relationship between biosensing characteristics with various properties of NiO matrix (structural, electrical etc.). The Ur/NiO/ITO/glass biosensor demonstrate very high sensitivity (66.7 μA/(mM)) with rapid time of response (5 s) and good linearity over a wide range of urea concentration (0.83–16.65 Mm). Lower Michaelis–Menten constant value (Km = 0.34 mM) ensures high affinity of Urease for urea. High electron transfer characteristics and long shelf life (20 weeks) are the key features of the fabricated urea biosensor.