Sensitivity Evaluation of a Dual-Finger Metamaterial Biosensor for Non-Invasive Glycemia Tracking on Multiple...

Area of Science:

• Biomedical Sensing
• Microwave Biosensors
• Non-invasive Glucose Monitoring

Background:

• Accurate, non-invasive glucose monitoring is a significant challenge in biomedical sensing.
• Existing methods often require invasive procedures or consumables.
• Advancements in microwave biosensor technology offer potential for non-invasive solutions.

Purpose of the Study:

• To develop and validate a high-sensitivity planar microwave biosensor for non-invasive glucose monitoring.
• To optimize the biosensor architecture for enhanced field confinement and resonance strength.
• To evaluate the performance of the biosensor using simulations and in vivo measurements.

Main Methods:

• Design and simulation of a 16-cell double-honeycomb (DHC-CSRR) microwave biosensor architecture.
• Full-wave simulations using Debye-modeled glucose phantoms on Rogers RO3210 and FR-4 substrates.
• In vitro measurements with glucose solutions and in vivo vector network analyzer (VNA) tests on human subjects.
• Development of a compact prototype with amplitude resolution as the primary metric.

Main Results:

• The optimized 16-cell DHC-CSRR array on Rogers RO3210 demonstrated significantly enhanced electric field intensity and transmission response sensitivity.
• In vivo VNA tests showed higher amplitude sensitivity with the Rogers substrate (9.35 × 10^-2 dB/(mg/dL)) compared to FR-4 (2.005 MHz/(mg/dL)).
• Dual-finger placement outperformed single-finger placement for both substrates.
• The prototype achieved high accuracy (R² = 0.980, RMSE = 2.316 mg/dL) with 100% of measurements in Zone A of the Clarke Error Grid Analysis.

Conclusions:

• The proposed non-invasive, consumable-free RF-based biosensor architecture shows significant promise for portable glucose monitoring.
• Substrate selection is crucial for optimizing amplitude sensitivity in RF-based glucose monitoring.
• Further research is needed for larger cohorts, flexible substrates, and regulatory approval.