Fano Resonance Sensor Based on Microhole Array Waveguides for Ultrasensitive Label-Free Biosensing

Area of Science:

• Nanotechnology
• Biosensing
• Optics

Background:

• Surface plasmon resonance (SPR) sensors are crucial for detecting trace biomolecules.
• Enhancing SPR sensor sensitivity is vital for advanced diagnostics.
• Existing Fano-type sensors have limitations in sensitivity and figure of merit.

Purpose of the Study:

• To develop an innovative Fano resonance biosensing platform for enhanced SPR sensitivity.
• To improve light-matter interaction through photon-plasmon coupling.
• To create a cost-effective and high-performance biosensor for biomolecule detection.

Main Methods:

• Fabrication of a sensor comprising a poly(methyl methacrylate) (PMMA) microhole array waveguide, MY-131-MC dielectric layer, and silver plasmonic layer.
• Utilizing photon-plasmon coupling to enhance Fano resonance.
• Modulating spatial coupling between photonic field and microhole membrane for electromagnetic field overlap.

Main Results:

• Achieved ultrahigh sensitivity of 56.24 μm/RIU for refractive index (RI) detection, an 11.4-fold improvement.
• Elevated figure of merit (FOM) to 2998.94 RIU^-1, surpassing conventional SPR sensors by two orders of magnitude.
• Demonstrated a limit of detection (LOD) of 81.8 pg/mL for carcinoembryonic antigen (CEA) detection with high selectivity, repeatability, and stability.

Conclusions:

• The developed Fano resonance biosensing platform offers a significant advancement in SPR sensor sensitivity.
• The photon-plasmon coupling enhancement strategy provides a novel approach for high-performance biosensing.
• This simple, cost-effective method presents a promising strategy for sensitive and selective detection of biomarkers.