Dual Kretschmann and Otto configuration fiber surface plasmon resonance biosensor

Area of Science:

• Optoelectronics
• Biomedical Engineering
• Materials Science

Background:

• Surface Plasmon Resonance (SPR) sensors are crucial for label-free biomolecular detection.
• Fiber-optic SPR sensors offer advantages in miniaturization and remote sensing.
• Indium Tin Oxide (ITO) exhibits unique refractive index properties useful for optical sensing.

Purpose of the Study:

• To develop and characterize a dual-resonance fiber SPR sensor for enhanced biological analysis.
• To investigate the sensor's performance in both Kretschmann and Otto configurations.
• To demonstrate the sensor's capability for real-time, label-free biomolecular interaction monitoring.

Main Methods:

• Fabrication of a fiber SPR sensor by sputtering ITO and Au layers onto an optical fiber.
• Characterization of the sensor using bulk refractive index (RI) sensitivity measurements.
• Application of the sensor for real-time monitoring of IgG/anti-IgG binding events.

Main Results:

• The ITO/Au coated fiber exhibited dual-resonance properties in visible and near-infrared regions due to ITO's refractive index dispersion.
• High RI sensitivities were achieved: 1345 nm/RIU (Kretschmann) and 1100 nm/RIU (Otto).
• Successful real-time, label-free detection of IgG/anti-IgG interaction was demonstrated.

Conclusions:

• The developed dual-resonance fiber SPR sensor is robust, ultra-compact, and highly sensitive.
• It offers a wide detection range suitable for various biological analyses.
• The sensor provides a promising platform for real-time biological monitoring applications.