Balanced Detection Method Using Optical Affinity Sensors for Quick Measurement of Biomolecule Concentrations

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Label-free optical biosensors typically require serial measurements from the reaction start point to determine biomolecule concentration, which is impractical for real-time applications.
• Existing methods lack efficiency and convenience for rapid, accurate biomolecule quantification in diverse settings.

Purpose of the Study:

• To develop and validate an alternative, convenient, and accurate method for determining biomolecule concentration using label-free optical biosensors.
• To enable single-point measurements for efficient biomolecule quantification, overcoming limitations of traditional serial detection methods.

Main Methods:

• The proposed method utilizes the fraction bound equation from the Langmuir adsorption model for concentration determination.
• Experimental validation involved detecting streptavidin-biotin complexes using on-chip optical sensors with active disk resonators and microfluidic circuits.
• A simultaneous parallel measurement scheme was employed to suppress signal fluctuations from external perturbations, mimicking balanced detection.

Main Results:

• The study successfully demonstrated a novel method for label-free biomolecule concentration determination with high accuracy.
• The method allows for concentration measurement relative to a reference sample using a single data point at any time.
• Simultaneous parallel measurements effectively suppressed external signal noise, enhancing detection reliability.

Conclusions:

• The developed method offers a practical and accurate alternative for label-free biomolecule quantification, overcoming the inconvenience of serial measurements.
• This approach is suitable for applications demanding fast and reliable detection responses.
• The integration with active disk resonators and microfluidics shows promise for advanced biosensing platforms.