Noise reduction by multiple referencing in surface plasmon resonance imaging.

Area of Science:

• Analytical Chemistry
• Biophysics
• Optical Sensing

Background:

• Surface plasmon resonance imaging (SPRi) is a label-free optical technique for detecting molecular interactions.
• Current SPRi methods face limitations due to intensity fluctuations, impacting signal-to-noise (S/N) ratios.
• Improving SPRi sensitivity is crucial for detecting subtle biological events.

Purpose of the Study:

• To enhance the analytical performance of SPRi by improving its signal-to-noise ratio.
• To investigate the effectiveness of splitting macroscopic sensing surfaces into microscopic sensing and referencing subareas.
• To demonstrate a novel method for reducing intensity fluctuations in SPRi.

Main Methods:

• Utilized surface plasmon resonance imaging with charge-coupled device (CCD) detection.
• Implemented a strategy of splitting the macroscopic sensing surface into multiple microscopic neighboring sensing and referencing subareas.
• Demonstrated the approach using the specific detection of biotin binding to a streptavidin monolayer.

Main Results:

• The multiple referencing approach significantly reduced intensity fluctuations across the sensing area.
• The signal-to-noise (S/N) ratio improved proportionally to the splitting factor.
• Achieved detection of refractive index variations as small as 3x10(-6) with an S/N ratio of approximately 10.
• Demonstrated effective sensing without the need for temperature stabilization.

Conclusions:

• Splitting sensing surfaces into multiple microscopic referencing subareas is an effective strategy to enhance SPRi analytical performance.
• This method offers a significant improvement in S/N ratio, enabling more sensitive detection of molecular binding events.
• The technique provides a robust and potentially cost-effective solution for advanced biosensing applications.