Fabrication of highly sensitive uric acid biosensor based on directly grown ZnO nanosheets on electrode surface

Here we report the direct synthesis of ZnO nanosheets (ZnO NSs) on the electrode surface by one step low temperature solution process and characterized in detail using various techniques. The directly grown ZnO NSs used for fabrication of uric acid biosensor (Nafion/Uricase/ZnO NSs/Ag/Si) and performance of fabricated has been examined for uric acid detection. This biosensor showed high sensitivity of 129.81 μA cm^-2 mM^-1 in wide-linear range (0.05-2.0 mM) with high correlation coefficient of R² = 0.9993. A rapid response time of ∼5 s, low detection limit of 0.019 μM (based on S/N ratio) and lower value of apparent Michaelis-Menten constant (Kmapp) of 0.026 mM was calculated for the fabricated biosensor. The lower value of Kmapp shows a high affinity between the uric acid and uricase immobilized on ZnO NSs. The anti-interference ability, reproducibility and long-term storage stability of biosensor were examined. These results suggests that our fabricated biosensors are highly reproducible, selective and stable for favorable determination of uric acid and can be effectively used for application in real samples with good precision and accuracy.