Modification of screen-printed carbon electrode (SPCE) by the Nafion functionalized silicon nanoparticles (SiNP/Naf) materials in non-enzymatic electrochemical sensor for uric acid (UA) detection

A non-enzymatic electrochemical sensor has been successfully developed to detect uric acid (UA) based on a modified screen-printed carbon electrode (SPCE) using Nafion functionalized silicon nanoparticles. Silicon nanoparticles (SiNPs) material is used because of their advantages, including its abundant availability, good biocompatibility, and adjustable porosity and surface area according to the synthesis method used. Nafion is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer that has been widely used for electrochemical sensors and is functioned as a stabilizer of the sensor. In this study, SiNPs material was successfully synthesized through the non-thermal chemical vapor deposition method. XRD diffractogram and SEM image confirmed its structure and morphology. The crystallinity of the produced SiNPs is 69.85%. SEM-EDS characterization was also carried out to confirm the success of the SPCE modification by SiNPs and SiNPs/Naf materials. The changes in the morphology of SPCE and the EDS spectrum that were measured indicated the success of the SPCE modification process for each stage. Cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry study were used to analyze the electrochemical characteristics and performance of non-enzymatic electrochemical sensors based on SPCE/SiNPs/Naf structures against uric acid analytes. Based on the results of electrochemical analysis, the sensitivity, detection limit, and quantification limit of the sensor are 0.01 μA.mM^-1. cm^-2, 0.21 μM, and 0.69 μM respectively in the linear measurement range of uric acid concentration of 10 - 1000 μM. Then, a sensor stability study was also carried out which resulted in an RSD value of 4.83%.