Additively manufactured microwave sensor for glucose level detection in saliva

Area of Science:

• Microwave Sensing
• Biomedical Engineering
• Material Science

Background:

• Diabetes mellitus is a global health concern, necessitating sensitive and accessible diagnostic tools.
• Current methods for glucose monitoring can be invasive or require complex laboratory analysis.
• There is a need for rapid, point-of-care devices for detecting biomarkers like glucose in bodily fluids.

Purpose of the Study:

• To propose and demonstrate a novel ink-on-glass microwave sensor for biomedical applications.
• To utilize Aerosol Jet Printing (AJP) for fabricating a compact, high-sensitivity sensor.
• To showcase the sensor's capability in detecting trace amounts of glucose in saliva as a diabetes biomarker.

Main Methods:

• Fabrication of a single-layer coplanar waveguide sensor with arc-shaped interdigital fingers using AJP.
• Integration of a circular geometry feature to ensure proper droplet placement on the sensor surface.
• Characterization of the sensor's response to varying glucose concentrations in artificial saliva within the K-band frequency range (20-30 GHz).

Main Results:

• The sensor demonstrated high sensitivity to changes in the electrical properties of the material under test (MUT).
• A 0.5 µL droplet of artificial saliva was sufficient for analysis, showing proportional changes in the transmission coefficient with glucose concentration.
• The sensor successfully distinguished 10 mg/100 mL glucose in saliva and exhibited monotonic changes in the 20-26 GHz range.

Conclusions:

• The developed ink-on-glass microwave sensor is a promising tool for non-invasive glucose detection in saliva.
• AJP technology enables the cost-effective fabrication of sensitive microwave sensors for biomedical diagnostics.
• The sensor's design and performance indicate potential for detecting other substances in liquids.