A hydrodynamic focusing microchannel based on micro-weir shear lift force

Area of Science:

• Biotechnology
• Microfluidics
• Analytical Chemistry

Background:

• Traditional flow cytometers often require complex sheath fluid systems for particle focusing.
• Microfluidic devices offer miniaturization and reduced reagent consumption for cell analysis.

Purpose of the Study:

• To develop and validate a novel microflow cytometer utilizing a micro-weir structure for particle focusing.
• To assess the focusing performance and reliability of the proposed microfluidic device for particle sorting and counting.

Main Methods:

• Fabrication of a micro-weir microchannel on stress-relieved glass substrates.
• Numerical simulations to analyze particle behavior within the microchannel.
• Experimental characterization using fluorescent particles (5 μm and 10 μm) and optical detection.

Main Results:

• Micro-weir structures effectively confined particle streams to the microchannel center without shear flow.
• Experimental results demonstrated one-by-one particle passage through the detection region.
• High focusing performance achieved: 99.76% for 5-μm beads and 99.57% for 10-μm beads.

Conclusions:

• The proposed microflow cytometer with a micro-weir design enables efficient and reliable particle focusing.
• This technology facilitates accurate sorting and counting of particles with varying diameters.
• The device presents a promising advancement in microfluidic-based analytical instrumentation.