Overpotential-controlled deposition of porous platinum for non-enzymatic glucose detection

Porous Pt electrodes are highly effective for non-enzymatic continuous glucose monitoring (CGM) due to their superior electrochemical activity and wide dynamic range. However, galvanostatic deposition, commonly used to apply Pt to CGM electrodes, is vulnerable to manufacturing tolerances and surface conditions. These issues cause potential changes to maintain current density, affecting reduction kinetics and influencing the morphology and roughness of the deposited Pt. In this study, we investigated the relationship between the deposition overpotential of Pt sensing materials and sensor performance using a potentiostatic method. We fabricated a microneedle-based CGM device with a three-electrode system. Pt sensing materials were deposited on the electrodes at different overpotentials, and the resulting Pt morphology and electrochemical surface area were investigated. Cyclic voltammetry was used to investigate the glucose oxidation mechanisms, while chronoamperometry was used to evaluate the sensitivity, reaction order and rate constant of glucose sensing. A coefficient of determination of 99 % was obtained for the relationship between sensor output current and glucose concentration over a wide range from 0 to 400 mg/dL. The results presented here can provide valuable insight into the optimization of Pt deposition for improved CGM sensor performance.