Ada Raucci, Wanda Cimmino, Cosimo Manna, Panagiota M. Kalligosfyri, Gennaro Persico, Michele Spinelli, Angela Amoresano, Waleed Alahmad, Stefano Cinti
This research presents an innovative all-in-one 3D-printed electrochemical biosensor for noninvasive detection of uric acid in saliva. Uric acid is a key biomarker for monitoring disorders such as gout and kidney disease as well as assessing the progression of metabolic conditions. The 3D-printed platform integrates a microwell, saliva collection module, and a three-electrode system, including carbon black and Prussian-blue-modified electrodes with immobilized uricase, into a single compact device, streamlining the sampling-to-detection workflow. Initial optimization using screen-printed electrodes on polyester films with differential pulse voltammetry established baseline performance, while the fully integrated 3D-printed system, with the incorporation of uricase, achieved detection limits of 0.09 μM in phosphate-buffered saline and 0.1 μM in 20% diluted saliva. Comparative analysis with high-performance liquid chromatography confirmed the accuracy and reliability of the measurements. By combining nanomaterial-enhanced electrodes, enzymatic recognition, and additive manufacturing, this platform offers a portable, user-friendly, and low-cost solution for point-of-care uric acid monitoring. The integrated design minimizes sample handling, prevents contamination, and enables hygienic, noninvasive collection. This approach facilitates rapid diagnostic testing and real-time health monitoring, providing actionable information for personalized patient care. Overall, the fully 3D-printed biosensing system represents a significant advance in electrochemical biosensors, demonstrating the potential to improve the clinical management of uric acid-related conditions while enabling scalable, accessible, and point-of-care diagnostics.