A Novel Uric Acid Biosensor Based on Regular Prussian Blue Nanocrystal/ Upright Graphene Oxide Array Nanocomposites

Background: Uric acid (UA) is an important metabolic intermediate of the human body. Abnormally high levels of UA will cause diseases. However, UA monitoring with commercial products relies on invasive blood collection, which not only causes pain in patients but also risks bacterial infections and skin irritation. In recent years, new models of noninvasive detection through body surface penetration have raised higher expectations for the sensitivity of uric acid detection, and rapid, accurate and highly sensitive UA sensors will become powerful tools for the diagnosis of UA-related diseases. Objective: This study aimed to identify the differences in catalytic efficiency between regular PB from spray crystallization (RPB) and irregular PB from electrodeposition (EDPB), which is used for fabricate a high sensitive uric acid sensor. Methods: Regular Prussian blue nanocrystals (RPB) were grown on graphene oxide flakes (GO), on the surface of a custom screen-printed carbon electrode (SPCE), using a spray method assisted by a constant magnetic field (CMF). After immobilizing uricase, the uric acid biosensor Uricase/RPB/CMF-GO/SPCE was obtained. Results: The detection range of the sensor response to UA was 0.005~2.525 mM, and the detection limit was as low as 3.6 μM. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that compared to amorphous electrodeposited Prussian blue (EDPB), RPB more favorably accelerated electron transport. Conclusion: This novel uric acid biosensor exhibits high sensitivity over a wide concentration range, strong anti-interference ability, and good stability and reproducibility. Thus, it has good application prospects for determining uric acid in physiological samples.