Optimization and development of a Cu-NPs@UiO-66-based electrochemical sensor for creatinine detection using box-Behnken design

Herein, we have designed a novel Cu-NPs@UiO-66 composite by anchoring copper nanoparticles (Cu-NPs) directly into the porous UiO-66 framework, specifically aiming to overcome the typical conductivity limitations of metal-organic frameworks in electrochemical applications. Both structural analyses and electrochemical testing validated that this integration significantly accelerates electron transfer and boosts electrocatalytic activity. To maximize sensor performance, we fine-tuned the experimental variables using a Box-Behnken Design (BBD) under response surface methodology (RSM). When deployed under these optimized parameters, the developed sensor outperformed UiO-66, delivering higher sensitivity, a noticeably lower detection limit of 50 pM, and a more robust response to creatinine, with a dynamic range from 50 pM to 2 μM. Beyond its strong selectivity, stability, and reproducibility, the platform proved its practical utility in complex matrices by accurately analyzing real serum samples (yielding reliable recoveries between 83.3% and 103.3%).