Non-invasive detection of urinary creatinine levels using a non-enzymatic electrochemical sensor with pectin-assisted Cu electrodeposition

Non-invasive creatinine monitoring is an attractive alternative to blood sampling for the assessment and management of chronic kidney disease. For this purpose, a non-enzymatic electrochemical sensor was introduced for non-invasive measurement of urinary creatinine levels. This sensor was prepared by utilizing ion exchange between pectin carboxyl groups and Cu2+ to promote uniform deposition of Cu on screen-printed carbon electrode (denoted as Pectin-Cu/SPCE). This promising pectin-assisted Cu electrodeposition method prepares a sensor with a low detection limit of 9.6 mu M for creatinine and a detection range of 20-1000 mu M. Furthermore, the improved sensitivity of this sensor is attributed to the rapid movement of Cu2+ and Cu2+-creatinine complexes on the electrode surface, which enhances the oxidation reaction. Also, this sensor demonstrates outstanding inter-batch reproducibility (n = 6) and good storage stability for 21 days. Moreover, this sensor can directly detect creatinine in diluted human urine without the need for complex pre-processing. The results were compared with the enzymatic method, and the accuracy was between 92.32 % and 97.87 %. As a result, this Pectin-Cu/SPCE-based non-enzymatic electrochemical sensor shows potential as a non-invasive urinary creatinine detection tool in a clinical setting.