Self-referencing a single waveguide grating sensor in a micron-sized deep flow chamber for label-free biomolecular...

Area of Science:

• Biosensing Technologies
• Optical Instrumentation
• Microfluidics

Background:

• Environmental fluctuations are a major challenge for sensitive label-free biosensor design.
• Existing methods struggle to effectively compensate for common-mode noise.
• Accurate detection of biomolecular binding events requires robust signal stabilization.

Purpose of the Study:

• To develop a novel system for compensating environmental fluctuations in label-free biosensors.
• To generate a highly accurate reference signal from the same sensor used for detection.
• To enhance the purity and reliability of biomolecular binding signals.

Main Methods:

• Integration of microfluidics and optical instrumentation.
• Development of an image processing technique for signal generation.
• Utilizing a common-mode reference signal derived from the primary sensing element.
• Validation using computational fluid dynamics (CFD) simulations.

Main Results:

• Demonstrated successful compensation of common-mode noise (temperature, pressure, vibration).
• Achieved a purer binding signal through subtraction of the reference signal.
• Validated fluid dynamics and thermal characteristics via CFD simulations.
• Successful demonstration in bulk refractive index tests and biotin/streptavidin binding experiments.

Conclusions:

• The presented system effectively compensates for environmental fluctuations in label-free biosensing.
• The dual-signal approach significantly enhances the signal-to-noise ratio.
• The technique shows broad applicability for various biomolecular binding assays and control experiments.