Terahertz Asymmetric S-Shaped Complementary Metasurface Biosensor for Glucose Concentration

Area of Science:

• Metamaterials and Nanophotonics
• Biosensing Technology
• Terahertz Spectroscopy

Background:

• Terahertz (THz) metasurfaces offer unique electromagnetic properties for sensing applications.
• Asymmetric designs can enable novel resonance phenomena for enhanced field confinement.
• Biosensing requires high sensitivity and specificity for disease detection, particularly for glucose monitoring.

Purpose of the Study:

• To design and investigate a free-standing terahertz metasurface biosensor.
• To explore the potential of asymmetric S-shaped complementary resonators for biosensing.
• To evaluate the device's performance in detecting various glucose concentrations relevant to diabetes.

Main Methods:

• Fabrication of a free-standing metasurface composed of asymmetric S-shaped complementary resonators.
• Analysis of frequency response by varying geometrical asymmetry under normal incidence in transmission mode.
• Testing the metasurface as a biosensor for glucose concentrations (54–342 mg/dL) under two sample coating scenarios.
• Characterization of resonance frequency shifts and wavelength sensitivity.

Main Results:

• The asymmetric metasurface design excited quasi-bound states in the continuum resonance, leading to excellent field confinement.
• Significant resonance frequency redshifts of up to 286.6 GHz were observed for high glucose concentrations (342 mg/dL).
• A high wavelength sensitivity of 322,749 nm/RIU was achieved, demonstrating a 2.3-fold enhancement over previous studies.

Conclusions:

• The developed terahertz metasurface biosensor demonstrates high sensitivity and significant resonance shifts for glucose detection.
• The device shows promise for non-invasive monitoring and diagnosis of hypoglycemia and hyperglycemia.
• This technology could advance point-of-care diagnostics for diabetes management.