U-fiber-based biosensor for temperature-compensated acetylcholine-specific measurement

Area of Science:

• Biomedical Engineering
• Optical Biosensing
• Analytical Chemistry

Background:

• Acetylcholine (ACh) is a crucial neurotransmitter with implications in various physiological and pathological processes.
• Accurate and sensitive detection of ACh is vital for diagnostics and research.
• Traditional biosensors often face challenges with temperature interference and limited sensitivity.

Purpose of the Study:

• To develop a U-fiber-based biosensor capable of specific and temperature-compensated acetylcholine detection.
• To integrate surface plasmon resonance (SPR) and multimode interference (MMI) effects in a single U-shaped fiber.
• To enhance biosensor performance by addressing temperature-related signal fluctuations.

Main Methods:

• Simultaneous realization of SPR and MMI effects within a U-shaped optical fiber structure.
• Immobilization of acetylcholinesterase (AChE) onto the optical fiber for label-free ACh detection.
• Utilizing a sensitivity matrix to decouple refractive index (RI) changes and compensate for temperature variations.

Main Results:

• Achieved high RI sensitivities of 3042 nm/RIU (MMI) and 2958 nm/RIU (SPR).
• Demonstrated low temperature sensitivities of -0.47 nm/°C (MMI) and -0.40 nm/°C (SPR), indicating effective temperature compensation.
• Successfully performed label-free detection of acetylcholine with a detection limit of 30 nM, exhibiting good stability and selectivity.

Conclusions:

• The U-fiber biosensor offers a novel approach for temperature-compensated, specific acetylcholine detection.
• The integrated SPR and MMI configuration significantly enhances sensor performance compared to traditional methods.
• This biosensor presents a valuable addition to fiber-optic SPR technology, suitable for direct insertion into small spaces.