High-performance uric acid detection using hierarchical NiO nanostructure-based biosensor

Abstract

Nanomaterials engineering combined with enzyme conjugation is driving advances in biosensing. In this study, an electrochemical biosensor based on the hierarchical NiO nanostructure and the uricase enzyme was constructed to provide high sensitivity and selectivity for uric acid (UA) detection. The hierarchical NiO nanostructure material was synthesized via a hydrothermal method and characterized in detail. The UA biosensor was constructed using a hierarchical NiO nanostructure fixed onto the screen-printed graphite electrode (SPGE), with physically adsorbed uricase on the nanomaterial surface, and Nafion (Nf). The electrochemical characteristics of the SPGE/NiO/uricase/Nf biosensor were studied using the cyclic voltammetry (CV) technique. CV analysis revealed that the fabricated SPGE/NiO/uricase/Nf biosensor responded rapidly to UA over a wide concentration range of 25-900 μM, exhibiting a high sensitivity of 423.5 ± 2.6 μA/mM/cm² and a detection limit of ~1.45 ± 0.12 μM. The biosensor successfully detected UA in human serum and artificial saliva samples. It also demonstrated excellent reproducibility (RSD of < 6.5%), reusability (retaining ~90.4% of its initial current response for up to 18 days), and strong anti-interference capability. The enhanced results from the synergistic electrochemical properties of the hierarchical NiO nanostructure and the uricase enzyme, where NiO provides improved electron transfer and uricase enhances selective electrocatalytic activity towards UA. These results support its potential application in clinical diagnostics.