A Wide Dynamic-Range Polarization-Controlled SPR Imaging Method for High-Throughput Biomolecular Detection.

Area of Science:

• Biophotonics
• Biosensing
• Analytical Chemistry

Background:

• Surface Plasmon Resonance (SPR) is a label-free technique for real-time biomolecular detection.
• Conventional SPR systems face limitations in throughput, sensitivity, and dynamic range.

Purpose of the Study:

• To develop a polarization-controlled intensity-modulated SPR imaging (SPRi) system integrated with a microfluidic chip.
• To overcome the limitations of traditional SPR by enhancing sensitivity, throughput, and dynamic range.

Main Methods:

• Utilized the phase difference between s- and p-polarized light for SPR excitation.
• Incorporated a polarizer, quarter-wave plate, and analyzer to amplify refractive index (RI) changes into intensity signals.
• Integrated a 12-channel microfluidic chip for high-throughput analysis.

Main Results:

• Achieved a high refractive index sensitivity of 24,300 ± 426 au/RIU.
• Demonstrated a resolution of (9.96 ± 0.32)×10^-7 RIU over a broad dynamic range (1.331-1.410 RIU).
• Showcased high sensitivity in biomolecular assays, with a detection limit of 1.56 pg/mL for D-biotin and 0.06586 au/(μg/mL) for mouse IgG.

Conclusions:

• The developed SPRi system offers a robust, high-throughput solution for label-free biomolecular detection.
• This technology has significant potential for applications in biomedicine, environmental monitoring, and pharmaceutical development.
• The polarization-controlled intensity modulation significantly enhances detection capabilities.