A Graphene/Prussian Blue/Rhodium Printed Biosensor for Detecting Uric Acid and Its Clinical Evaluation

Uric acid is produced via the purine metabolism pathway, and an abnormal level of uric acid could lead to serious diseases and complications, such as gout, renal, and cardiovascular diseases. A rapid, convenient, and accurate detection of uric acid is highly desired for healthcare applications. Here, we report a screen-printed amperometric biosensor for uric acid based on a composite ink consisting of graphene, Prussian blue (PB), and rhodium (Rh)/carbon catalyst. The working electrode is printed by a graphene/PB ink and an Rh/carbon (Rh/C) ink sequentially with drying in between. The linear detection range for uric acid is 0.04–0.8 mM with a response time of 30 s and a detection limit of $0.55 ~\mu \text{M}$ . The biosensor could be stored in a refrigerator at 4 °C for 80 days without a significant decrease in response. Furthermore, compared to the detection results from the clinical standard method, the relative error of the biosensor is within 20% for detecting uric acid in human blood samples. It is anticipated that this work could advance exciting fundamental studies for uric acid-sensing devices, as well as the clinical applications for the detection of uric acid.