Fabrication of Electrochemical Biosensor Using Zinc Oxide Nanoflowers for the Detection of Uric Acid

A label-free electrochemical biosensor has been developed using zinc oxide nanoflowers (ZnONFs) for the detection of uric acid concentration in human blood serum. ZnONFs have been synthesized by a hydrothermal process and characterized with several techniques such as ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR) studies, X-ray diffraction (XRD) study, Raman spectroscopy, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) and electrochemical analyzer to confirm the formation of nanoflowers and fabrication of electrode and bio-electrodes for uric acid detection. Zinc Oxide nanoflowers have been deposited onto indium–tin oxide (ITO) substrate through electrophoretic deposition technique, and the biosensor has been fabricated by immobilizing urate oxidase (UOx) enzyme onto ZnONFs/ITO electrode surfaces. Further, electrochemical studies have been performed with immobilized UOx/ZnONFs/ITO bio-electrode as a function of uric acid concentrations. It has been found that the fabricated uric acid biosensor shows a high sensitivity (10.38 μA/mM/cm2) and a limit of detection of 0.13 mM in the range of 0.005 to 1.0 mM. This study demonstrates the potential use of ZnONFs for the construction of sensitive biosensors for uric acid detection.