A monolithic silicon optoelectronic transducer as a real-time affinity biosensor.

Area of Science:

• Optoelectronics
• Biomedical Engineering
• Nanotechnology

Background:

• Real-time affinity biosensors are crucial for rapid biological analysis.
• Existing biosensors face challenges in sensitivity and multiplexing capabilities.
• Monolithic integration of optical and electronic components offers a promising approach.

Purpose of the Study:

• To develop and characterize a novel optical real-time affinity biosensor.
• To demonstrate the sensor's capability for sensitive and multiplexed analyte detection.
• To evaluate the impact of surface modification and silver enhancement on sensor performance.

Main Methods:

• Fabrication of a monolithic silicon optoelectronic transducer with integrated light sources, optical fibers, and detectors.
• Surface functionalization including hydrophilization, silanization, and bioactivation with probes.
• Real-time monitoring of binding events using a microfluidic module and evanescent wave detection.
• Evaluation using biotin-streptavidin assay and silver enhancement technique.

Main Results:

• Achieved detection limits of 3.8 pM (continuous flow) and 13 pM (stopped flow) for gold nanoparticle-labeled streptavidin.
• Enhanced sensitivity with silver plating, reaching a detection limit of 20 fM.
• Demonstrated simultaneous detection of two analytes (streptavidin and anti-mouse IgG) on a single chip.

Conclusions:

• The developed optical biosensor offers high sensitivity and real-time monitoring capabilities.
• The monolithic silicon optoelectronic transducer provides an efficient and integrated platform.
• The sensor demonstrates significant potential for multiplexed and ultrasensitive bioanalytical applications.