New Disposable Electrochemical Paper‐based Microfluidic Device with Multiplexed Electrodes for Biomarkers Determination in Urine Sample

A disposable electrochemical paper‐based analytical device was constructed based on use of sequential analysis with multiplexed working electrodes and applied for the determination of glucose, creatinine, and uric acid. The device was constructed with 16 microfluidic channels, with 16 working electrodes arranged in four set with four components surrounding the sample injection hole. In addition, a commercial multiplexing module was used, which allowed for multiplexing of the 16 working electrodes. This design allowed for radial and homogeneous sample elution to each sensing spot for high throughput analysis. In the multiplexed determinations, distinct electrochemical procedures were employed for each analyte. Furthermore, each working electrode spot was modified to increase the respective analytical signals. For glucose detection, the sensor was based on electron mediation by ferrocenecarboxylic acid over the modified surface with glucose oxidase. The principle for creatinine detection was based on electrochemical reduction of non‐complexed Fe³⁺ in excess after complex formation between Fe³⁺ and creatinine in the chemical step. The anodic peak current responses for uric acid detection increased due to working electrode surface modification with carbon black nanoparticles. In the multiplexed analysis, the device provided limits of detection of 0.120 mmol L^?1, 0.084 mmol L^?1, and 0.012 mmol L^?1 for glucose, creatinine, and uric acid, respectively. The developed device was successfully applied in the analyses of real urine samples.