Micro-Resonator Based Bivariate Detection of Glucose Concentration With Phenylboronic Acid Functionalized Reduced Graphene Oxide

We developed a biosensor based on radio frequency micro-resonator for sensitive detection of aqueous glucose solutions. The device incorporates a modified interdigital capacitor-based multilayer resonator realized using integrated passive device technology. In addition, reduced graphene oxide was functionalized by phenylboronic acid aided with graphene oxide for the selective binding of glucose molecules under an electromagnetic field, resulting in a reliable concentration-specific resonance characteristic of the samples. The resonance frequency and bivariate (in terms of magnitude dip and phase reversal of the reflection coefficient) characteristics were found to be linearly related to the glucose concentration, thereby demonstrating the utility of the proposed microwave passive sensor in the detection of glucose with a sensitivity of 0.32 MHz per mg · dL
^-1
. Furthermore, the corresponding variation in the capacitance and the impedance was accessed for each concentration of the glucose solutions.