Selective Impedimetric Laser-Induced Graphene Sensor for Glucose Detection

This work presents a novel approach to the fabrication of interdigitated electrodes (IDEs) using flexible polymer substrates. Two substrates, polyimide (PI) and polyetherimide (PEI), are compared alongside two manufacturing techniques: direct laser tracing and silver ink printing. The IDEs produced are applied to the detection of glucose and salt content in biological samples through impedance measurements. The analysis of impedance response enables the quantification of the relationship between signal magnitude and analyte concentration for both sensors and solutions, allowing for the estimation of unknown concentrations based on measured impedance values. The results obtained demonstrate the potential of the manufactured electrodes for non-invasive biosensing applications. This study highlights the sensitivity of these sensors for detecting glucose concentrations in the range of hypo- and hyperglycemia (0.7-1.8 mg/mL) and salt content, revealing their potential for use in real-time monitoring of important biological parameters. To further enhance analyte discrimination, an equivalent circuit model has been developed to describe the system’s electrical behavior, enabling effective differentiation between glucose and salt solutions. The findings suggest that the combination of flexible, low-cost substrates and impedance-based detection holds promise for advancing personalized health monitoring technologies, particularly for glucose and electrolyte balance.