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

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 degrees 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 mu A/(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 (K-m = 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.