A method for detecting forward scattering signals on-chip with a photonic-microfluidic integrated device

Area of Science:

• Photonics
• Microfluidics
• Optical Engineering

Background:

• Traditional flow cytometry systems often require bulky external optics for signal detection.
• Integrating optical components onto microfluidic devices presents challenges in achieving optimal excitation and collection geometries.
• On-chip detection enhances miniaturization and simplifies complex biological analyses.

Purpose of the Study:

• To demonstrate a photonic integrated microfluidic device capable of on-chip optical excitation and forward scatter collection.
• To develop a novel lens system for tailored beam shaping and efficient on-chip signal detection.
• To evaluate the performance and reliability of the integrated device for particle detection.

Main Methods:

• Fabrication of a planar photonic integrated microfluidic device with on-chip optics.
• Design and implementation of a modified lens system with a notch for on-chip forward scatter collection.
• Generation of a 10 μm excitation beam geometry for particle interrogation.
• Simultaneous on-chip forward scatter and free-space side scatter collection.
• Performance evaluation using 5 μm polystyrene beads.

Main Results:

• The device successfully performed on-chip optical excitation and forward scatter collection.
• The modified lens system enabled a focused 10 μm beam and effective on-chip collection.
• Simultaneous free-space side scatter collection was achieved, enhancing signal-to-noise ratio (SNR).
• Demonstrated excellent performance metrics: 0.4% false positive rate, 6.8% missed events rate, and 96.3% coincident rate.

Conclusions:

• The developed photonic integrated microfluidic device offers a compact and efficient solution for particle analysis.
• The on-chip forward scatter collection design enhances detection reliability and accuracy.
• The device's performance is suitable for a wide range of applications requiring sensitive particle detection.