Quantitative detection of uric acid through ZnO quantum dots based highly sensitive electrochemical biosensor.

Highlights • An elementary precipitation method was used to synthesize ZnO QDs. • ZnO QDs guiding layer facilitate immobilization of uricase and showed high sensitivity, and reproducibility. • A three electrode based electrochemical biosensor was successfully fabricated for uric acid analysis. • Biosensor showed a wide linear range of detection 1–10 mM, covers the physiological range present in urine sample. Abstract Current trends in biosensors research include the application of nanomaterials to; provide a stable platform for immobilization and improving sensitivity. Quantum dots (QDs) are highly dispersed and extremely small (4–6 nm) particles that have been recognized to greatly increase the sensitivity by providing a larger surface area for binding of enzymes on the surface of the electrodes. Zinc oxide quantum dots (ZnO QDs) were synthesized through precipitation method and were characterized using TEM, UV–vis, and Raman spectroscopy to determine their properties. In this research work, we investigate the scope of ZnO QDs for the immobilization of uricase, an acidic enzyme having low isoelectric point, on the surface of nanostructured guiding layer for the detection of uric acid (UA). A three electrode based electrochemical biosensor was successfully fabricated using screen printing technique. The carbon electrode was modified with a thin film of ZnO QDs; the prepared thin film was utilized as working electrode. The ZnO QDs were subsequently functionalized with uricase to fabricate a selective uric acid sensor. The printed electrochemical sensor showed a linear response over a range of 1 mM–10 mM with a high sensitivity of 4.0 μA/mM cm−2. As a result, the procedures developed here are useful for the development of technologies accomplished of meeting the massive market demand of biosensors. [ABSTRACT FROM AUTHOR]