Surface modified ZnONFs with Oleic acid to fabricate nanobiosensors for uric acid detection

In the present study, we employed an ex-situ process to modify the surface of zinc oxide nanoflowers (ZnONFs). Initially, we synthesized ZnONFs using the hydrothermal method. Subsequently, we capped the synthesized ZnONFs using the ultra-sonication method. The capped ZnONFs were then extensively characterized using various techniques, including UVvisible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. We then electrophoretically coated the synthesized capped ZnONFs onto bare ITO electrodes to create uric acid biosensors. The bioelectrode, UOx/Oleic acid-ZnONFs/ITO, was formed by applying EDC-NHS to the Oleic acid ZnONFs/ITO electrode and then chemically immobilizing the Uricase enzyme. We evaluated the performance of the UOx/Oleic acid-ZnONFs/ITO bioelectrode by measuring its ability to detect uric acid concentrations in a linear range from 0.005 to 1.0 mM. The bioelectrode demonstrated a low limit of detection (LOD) of 0.0044 µA/mM and an outstanding sensitivity of 685.4 µA/mM/cm². The fabricated uric acid biosensors exhibited a shelf life of over 30 days with a single interval.