Pretreated Screen-Printed Carbon Electrode and Cu Nanoparticles for Creatinine Detection in Artificial Saliva

Creatinine is the final metabolic product of creatine in muscles and a widely accepted biomarker for chronic kidney disease. In this work, we present a non-enzymatic sensor based on an electrochemical pretreated screen-printed carbon electrode (PTSPCE) with electrodeposited Cu nanoparticles (CuNPs). To function in a PoC format, the prepared PTSPCE/CuNPs non-enzymatic sensors were used as disposable elements in a portable potentiostat. The pretreatment using mild anodic and cathodic potentials in PBS resulted in an increased electroactive surface area and improved conductivity, confirmed by cyclic voltammetry and electrochemical impedance. Moreover, the detection through the CuNPs–creatinine interaction showed an enhanced performance in the PTSPCE surface compared to the bare electrode. The optimized PTSPCE/CuNPs sensor showed a linear working range from 10 to 160 μM (R2 = 0.995), a sensitivity of 0.2582 μA·μM−1 and an LOD of 0.1 μM. The sensor analytical parameters covered the requirements of creatinine detection in biofluids such as blood and saliva, with a low interference of common biomarkers such as urea, glucose, and uric acid. When evaluated in Fusayama/Meyer artificial saliva, the PTSPCE/CuNPs showed an average recovery rate of 116%. According to the observed results, the non-enzymatic PTSPCE/CuNPs sensor can potentially operate as a creatinine early screening system in PoC format.