title: Zinc oxide nanorods modified indium tin oxide surface for amperometric urea biosensor.
abstract: ZnO nanorods (ZnONR) grown onto indium-tin-oxide (ITO) coated glass surface using zinc nitrate hexahydrate/hexamethylenetetramine (HMT) in aqueous phase has been utilized for urea biosensor. Urease (Urs) was immobilized onto ZnONR/ITO at physiological pH via electrostatic interactions between Urs and ZnO to fabricate Urs/ZnONR/ITO bioelectrode. ZnONR/ITO electrode has been characterized using XRD, FE-SEM techniques and Urs/ZnONR/ITO bioelectrode using electrochemistry. The XRD and FE-SEM measurements confirm the formation of ZnO nanorods in wurtzite structure. Cyclic voltammetric and amperometric measurements on the Urs/ZnONR/ITO biolectrode for urea concentrations in the range of 1-20 mM reveal 0.4 microA mM(-1) sensitivity, with a response time of 3 seconds, and a detection limit of 0.13 mM. The Michaelis-Menten constant (Km) was calculated to be 9.09 mM. Results indicate that ZnO nanorods provide suitable microenvironment for urease immobilization and can be utilized in biosensor design and other biological applications.
authors: Department of Mechanical Engineering, University of Puerto Rico, Mayagüez, PR 00681-9000.
authors: Netzahualcóyotl
authors: N
authors: Palomera
authors: Marcia
authors: M
authors: Balaguera
authors: Sunil K
authors: SK
authors: Arya
authors: Samuel
authors: S
authors: Hernández
authors: Maharaj S
authors: MS
authors: Tomar
authors: Jaime E
authors: JE
authors: Ramírez-Vick
authors: Surinder P
authors: SP
authors: Singh
mesh_terms: D015374:Biosensing Techniques; D006863:Hydrogen-Ion Concentration; D007204:Indium; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes; D014508:Urea / Q000032:analysis*; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D007204:Indium; D014508:Urea; D015034:Zinc Oxide