Metamaterial-Inspired Microwave Microfluidic Sensor for Glucose Monitoring in Aqueous Solutions

A high-sensitive microwave microfluidic sensor based on improved split ring resonator (SRR) for detecting glucose concentration in aqueous glucose solutions is proposed. The novel SRR design of the proposed sensor incorporates inter-digital capacitor (IDC) in the gap of the resonator for enhanced electric field concentration over a larger surface area, which provides higher sensitivity for testing of dielectric liquids. In order to facilitate the measurement of lossy fluids using the proposed sensor, a microfluidic channel is appropriately positioned over the IDC region of the SRR, through which the glucose solutions are made to pass. The microfluidic channel, made of polydimethylsiloxane (PDMS) is biocompatible, economical, which is customized to preserve the sample from external contamination. Aqueous solutions with glucose concentrations ranging from 0 to 5000 mg/dl are characterized based on the shift in the resonant frequency and the normalized peak attenuation of the SRR sensor. The measured sensitivity of the proposed PDMS integrated novel SRR sensor for glucose testing is found to be 2.60E-02 MHz/mgdl(-1), which is a fair improvement compared to earlier proposed sensors employing similar sensing methodologies. The applicability of the proposed sensor for quantitative analysis of aqueous glucose solutions is verified using both simulation and experimental procedures.