Flexible Nonenzymatic Glucose Biosensor Based on Magnetoelectrochemical Deposition of Cu

Abstract

Diabetes is a growing global health concern, driving the need for advanced glucose monitoring approaches. This study introduces a novel, flexible, nonenzymatic glucose biosensor fabricated using magnetoelectrochemical deposition of copper (Cu) onto an indium-tin-oxide (ITO) coated polyethylene terephthalate (PET) substrate. A custom 3D-printed electrochemical cell enabled controlled Cu deposition under magnetic fields ranging from 0 to 4195 G. The Cu-ITO glucose sensor fabricated in the presence of a 4195 G magnetic field (Mag-Cu-ITO) exhibited a significantly higher amperometric sensitivity of 1052 μA mM -1 . In comparison, the Cu-ITO sensor fabricated in the absence (i.e., 0 mT) of a magnetic field yielded a sensitivity of 688 μA mM -1 . The sensor demonstrated a linear response to glucose concentrations between 5 and 390 μM, covering relevant physiological glucose levels in human sweat. The sensor also showed excellent selectivity, exhibiting no significant response to common interferants usually found in sweat (i.e., caffeine, thiocyanate, uric acid, urea, and ascorbic acid). Electrochemical impedance spectroscopy (EIS) revealed a decrease in charge transfer resistance (R ct ) of the Mag-Cu-ITO sensor by 25% compared to the Cu-ITO sensor fabricated in the absence of a magnetic field, indicating improved electron transfer kinetics. The proposed Mag-Cu-ITO sensor offers a low-cost, nonenzymatic approach for continuous glucose monitoring in human sweat, leveraging magnetic field-assisted deposition as a sustainable and scalable fabrication method. These findings highlight the potential of magnetoelectrochemical deposition for enhancing biosensor performance in noninvasive biofluid analysis, paving the way for next-generation wearable glucose biosensors. Figure 1