Differential surface plasmon resonance imaging for high-throughput bioanalyses.

Area of Science:

• Biophotonics
• Surface Plasmon Resonance Imaging
• Biosensing

Background:

• Surface Plasmon Resonance (SPR) is a label-free optical technique widely used for studying biomolecular interactions.
• High-throughput SPR measurements are crucial for drug discovery and diagnostics.
• Existing imaging SPR methods face limitations in sensitivity and throughput.

Purpose of the Study:

• To introduce a new imaging technique for high-throughput surface plasmon resonance (SPR) measurements.
• To optimize SPR detection by utilizing a CCD camera and dual-wavelength imaging.
• To demonstrate improved detection limits and simultaneous measurement capabilities.

Main Methods:

• Application of a CCD camera for simultaneous processing of two images at different wavelengths from two laser diodes.
• Optimization of resonance conditions by tuning the angle of incidence for selected wavelength pairs.
• Differential image processing to achieve measurements near the shot noise limit.
• Strategic placement of the working point near the reflection minimum to enhance detection sensitivity.

Main Results:

• Achieved a noise level of 1.5 x 10(-6) refractive index units (RIU) for single 500 x 500 microm2 reaction areas.
• Reduced noise level to approximately 6 x 10(-7) RIU when averaging over five areas.
• Demonstrated simultaneous measurement of hybridization reactions for three different thiolated oligonucleotides.
• The system has the potential for simultaneous measurements of up to 400 binding reactions.

Conclusions:

• The developed dual-wavelength imaging SPR technique offers significant improvements in detection limits and throughput.
• Optimizing the working point near the reflection minimum is critical for enhanced sensitivity in imaging SPR.
• This technique provides a robust platform for high-throughput screening of biomolecular interactions.