Sol-gel-derived titanium oxide-cerium oxide biocompatible nanocomposite film for urea sensor

摘要

Sol-gel-derived biocompatible titanium oxide-cerium oxide (TiO_2-CeO_2) nanocomposite film was deposited onto indium tin oxide (ITO)-coated glass substrate by the dip-coating method. This nanobiocomposite film has been characterized using x-ray diffraction, Fourier transform infrared, atomic force microscope, and electrochemical techniques, respectively. The particle size of the TiO_2-CeO_2 nanobiocomposite film was found to be 23 nm. The urea biosensor fabricated by immobilizing mixed enzyme [urease (Urs) and glutamate dehydrogenase (GLDH)] on this nanobiocomposite showed a response time of 10 s, sensitivity as 0.9165 μAcm~(-2)mM~(-1), detection limit of 0.166 μM, and negligible effect due to interferants uric acid, cholesterol, glucose, and ascorbic acid. The value of Michaelis-Menten constant (K_m) estimated using Lineweaver-Burke plot as 4.8 raM indicated enhancement in the affinity and/or activity of enzyme attached to their nanobiocomposite. This bioelectrode retained 95% of enzyme activity after 6 months at 4℃.