Performance Enhancement of SPR Biosensor Using Graphene-MoS₂ Hybrid Structure

Area of Science:

• Materials Science
• Nanotechnology
• Biosensing

Background:

• Surface plasmon resonance (SPR) biosensors are crucial for detecting biomolecules.
• Enhancing the sensitivity of SPR sensors is essential for early disease diagnosis.
• Molybdenum disulfide (MoS2) and graphene offer unique electronic and optical properties for advanced sensor applications.

Purpose of the Study:

• To develop and characterize a high-sensitivity SPR biosensor utilizing MoS2 and graphene.
• To investigate the impact of MoS2 layer number on sensor performance.
• To evaluate the sensor's efficacy in detecting okadaic acid (OA) through competitive inhibition immunoassay.

Main Methods:

• Numerical simulations using the transfer matrix method (TMM) and finite difference time domain (FDTD).
• Fabrication of MoS2/graphene on Au substrate via PMMA-based wet transfer.
• Characterization using Raman spectroscopy and experimental validation with Kretschmann configuration.
• Competitive inhibition immunoassay for okadaic acid detection.

Main Results:

• The proposed SPR biosensor demonstrated a maximum sensitivity of 282°/RIU, approximately double that of conventional Au-based SPR sensors.
• Finite difference time domain (FDTD) simulations confirmed strong surface electric field generation by MoS2, enhancing sensitivity.
• Experimental results showed a very low limit of detection (LOD) of 1.18 ng/mL for OA, 22.6 times lower than conventional Au biosensors.

Conclusions:

• The developed MoS2/graphene-based SPR biosensor exhibits significantly enhanced sensitivity and detection capabilities.
• The sensor design shows great promise for sensitive and specific detection of analytes like okadaic acid.
• Potential applications include clinical diagnosis and advanced immunoassays requiring high sensitivity.