Optical weak measurement system with common path implementation for label-free biomolecule sensing.

Area of Science:

• * Physics
• * Chemistry
• * Materials Science

Background:

• * Traditional biosensing methods often require labels, adding complexity and cost.
• * Precise measurement of subtle changes in optical properties is crucial for label-free detection.
• * Weak value amplification offers a pathway to enhance measurement sensitivity.

Purpose of the Study:

• * To develop and demonstrate a reflection-type phase-sensitive weak measurement system for label-free biosensing.
• * To leverage weak value amplification for enhanced sensitivity in detecting biomolecular recognition.
• * To validate the system's robustness and applicability in real-time biomolecular interaction monitoring.

Main Methods:

• * Employing a phase-sensitive measurement of the polarization-dependent phase difference (p and s polarizations) during total internal reflection.
• * Utilizing weak value amplification to enhance the detection of minute phase shifts caused by biomolecular binding.
• * Implementing the sensing process on a silicon dioxide surface for robust and stable measurements.

Main Results:

• * Achieved a high resolution of 3.6×10^-6 refractive index units for sensing.
• * Demonstrated a stable and robust system by using p and s polarizations in a common optical path.
• * Successfully monitored the real-time biomolecular interaction between Immunoglobulin G (IgG) and Protein A.

Conclusions:

• * The developed phase-sensitive weak measurement technique is effective for label-free biosensing and chemical detection.
• * The system exhibits high sensitivity and robustness, suitable for real-time monitoring of biomolecular events.
• * This approach holds significant potential for advancing diagnostic tools and understanding molecular interactions.