High-Throughput Particle Concentration Using Complex Cross-Section Microchannels.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Biotechnology

Background:

• High-throughput particle and cell concentration is vital for numerous biomedical, clinical, and environmental applications.
• Existing microfluidic concentrators face limitations in separation efficiency and particle focusing.

Purpose of the Study:

• To develop and evaluate a passive spiral microfluidic concentrator with a complex cross-sectional shape for enhanced particle focusing and concentration.
• To introduce and validate a new parameter, the complex focusing number (CFN), for quantifying inertial focusing enhancement.

Main Methods:

• Design and fabrication of passive spiral microfluidic devices with combined rectangular and trapezoidal cross-sections.
• Experimental investigation of particle focusing and concentration using microchannels of varying widths (400 µm, 500 µm, 600 µm).
• Quantification of separation efficiency and concentration factor through particle analysis.

Main Results:

• The complex cross-section design resulted in a single, tight particle focusing line, outperforming simple geometries.
• A separation efficiency of approximately 98% was achieved with the 600 µm wide device.
• Recirculation enabled a 500-fold increase in sample concentration, with CFN independent of channel width but dependent on microchannel geometry.

Conclusions:

• The proposed complex cross-sectional microfluidic concentrator significantly enhances inertial focusing and particle concentration.
• The complex focusing number (CFN) is a valuable metric for evaluating the performance of such microfluidic devices.
• This technology holds promise for advancing the efficiency of inertial microfluidic devices in various applications.