Novel glucose sensor based on enzyme-immobilized 81° tilted fiber grating

Area of Science:

• Biomedical Engineering
• Optical Sensors
• Biosensing Technology

Background:

• Accurate glucose monitoring is crucial for diabetes management and disease diagnosis.
• Existing glucose sensors face challenges including sensitivity, selectivity, and thermal stability.
• Optical fiber sensors offer potential advantages due to their small size, immunity to electromagnetic interference, and remote sensing capabilities.

Purpose of the Study:

• To develop and characterize a novel optical fiber glucose sensor utilizing an 81° tilted fiber grating (81°-TFG).
• To investigate the sensor's performance in terms of sensitivity, linearity, and thermal cross-talk.
• To explore the potential applications of this sensor in various monitoring fields.

Main Methods:

• Fabrication of an 81°-TFG with a surface modified by aminopropyltriethoxysilane (APTES) and glucose oxidase (GOD).
• Assessment of surface modification effectiveness using confocal and fluorescence microscopy.
• Characterization of the sensor's response to glucose concentration by monitoring resonance wavelength shifts.

Main Results:

• The modified fiber surface and glucose detection induced a red-shift in the resonance wavelength.
• A good linear response was observed between wavelength shift and glucose concentration (0.0–3.0 mg/ml) with a sensitivity of 0.298 nm·(mg/ml)-1.
• The 81°-TFG sensor demonstrated lower thermal cross-talk, better linearity, and a higher Q-factor compared to GOD-immobilized long period grating (LPG) sensors.

Conclusions:

• The developed 81°-TFG based glucose sensor is sensitive and exhibits improved performance metrics.
• Further optimization by increasing grating length or using higher-order cladding modes can enhance sensitivity.
• The proposed technique holds promise for developing label-free, micro-structural sensors for food safety, clinical analysis, and environmental monitoring.