Label-free biosensing using a microring resonator integrated with poly-(dimethylsiloxane) microfluidic channels

Area of Science:

• Biophotonics
• Nanotechnology
• Biosensing

Background:

• Microring resonators offer label-free, real-time detection of biomolecules.
• Photonic integrated circuits enable quantitative detection for medical diagnostics and environmental monitoring.

Purpose of the Study:

• To design, fabricate, and characterize a highly sensitive, label-free microring optical resonator.
• To integrate the resonator with microfluidic channels for reduced sample consumption.
• To demonstrate real-time monitoring of biomolecular binding events.

Main Methods:

• Fabrication of a microring optical resonator integrated with poly-(dimethylsiloxane) microfluidic channels.
• In situ measurement of resonance wavelength shifts caused by changes in refractive index.
• Real-time monitoring of antibody immobilization, surface blocking, and antigen-antibody binding.
• Detection of human immunoglobulin G and human epidermal growth factor receptor 2.

Main Results:

• Achieved a detection limit of 0.5 µg/ml for human immunoglobulin G, 14 times lower than previous resonators.
• Demonstrated real-time monitoring of specific binding events.
• Verified the system's utility with human epidermal growth factor receptor 2 detection.
• The system requires only 30 µl of sample solution.

Conclusions:

• The developed microring optical resonator provides highly sensitive, label-free, real-time biomolecular detection.
• The integrated system enables quantitative biological sensing with minimal sample volume.
• This technology is adaptable for various medical diagnostic and environmental monitoring applications.