SPR Biosensor Based on Polymer Multi-Mode Optical Waveguide and Nanoparticle Signal Enhancement.

Area of Science:

• Biomedical Engineering
• Optoelectronics
• Nanotechnology

Background:

• Surface plasmon resonance (SPR) is a label-free optical technique widely used for detecting molecular interactions.
• Existing SPR biosensors often require complex instrumentation and are costly, limiting their widespread application.
• There is a need for sensitive, low-cost, and portable biosensing platforms for point-of-care diagnostics.

Purpose of the Study:

• To develop a novel SPR biosensor utilizing a planar-optical multi-mode (MM) polymer waveguide.
• To demonstrate the sensor's capability for detecting biomolecules in the nano-molar (nM) range.
• To evaluate the potential for low-cost, disposable lab-on-a-chip applications and multiplexed detection.

Main Methods:

• Fabrication of a planar-optical multi-mode polymer waveguide structure for SPR sensing.
• Characterization of the basic sensor's sensitivity and resolution using refractive index changes.
• Integration of an aptamer-functionalized, gold-nanoparticle (AuNP)-enhanced sandwich assay for specific biomarker detection (C-reactive protein - CRP).

Main Results:

• The basic SPR sensor exhibited a sensitivity of 608.6 nm/RIU and a measurement resolution of 4.3 × 10^-3 RIU.
• The enhanced SPR biosensor successfully detected C-reactive protein (CRP) with a response of 0.118 nm/nM.
• The multi-mode polymer waveguide design enables a simple and cost-effective platform.

Conclusions:

• The developed SPR biosensor based on a multi-mode polymer waveguide offers high sensitivity and resolution for biomolecule detection.
• The aptamer-functionalized, AuNP-enhanced assay provides specific and sensitive detection of biomarkers like CRP.
• The sensor is suitable for low-cost, disposable lab-on-a-chip applications, with potential for fast and multiplexed biomarker analysis on a single platform.