Micro fluorescent analysis system integrating GaN-light-emitting-diode on a silicon platform

Area of Science:

• Microfluidics and Analytical Chemistry
• Optoelectronics and Silicon Micromachining
• Biomedical Engineering

Background:

• Traditional fluorescence analysis systems can be bulky and expensive.
• There is a need for miniaturized, integrated platforms for on-site or point-of-care fluorescent detection.

Purpose of the Study:

• To propose and demonstrate a novel micro fluorescence analysis system integrated onto a silicon platform.
• To utilize silicon micromachining for the monolithic integration of a light source, micro-channels, and detector.

Main Methods:

• Fabrication of a silicon-based system integrating a Gallium Nitride (GaN) light-emitting diode (LED) and a Silicon Photodiode (Si-PD).
• Integration of Polydimethylsiloxane (PDMS) micro-channels for sample handling.
• Utilization of a ring-shaped GaN-LED and dark-field optics for fluorescence excitation and detection.

Main Results:

• Successful integration of GaN-LED, PDMS micro-channels, and Si-PD on a silicon substrate.
• Demonstrated detection of fluorescein isothiocyanate (FITC) dye with measured noise of 0.57 pA.
• Achieved a sensitivity of 1.21 pA μM⁻¹ and a limit of detection of 469 nM for FITC.

Conclusions:

• The proposed silicon-based micro fluorescence analysis system is compact and effective.
• The integrated optoelectronic and microfluidic components enable sensitive fluorescent detection.
• This technology holds potential for developing portable and cost-effective analytical instruments.