Multistage microfluidic cell sorting method and chip based on size and stiffness

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cancer Diagnostics

Background:

• High-performance sorting of circulating tumor cells (CTCs) is crucial for liquid biopsies.
• Conventional size-based methods like deterministic lateral displacement (DLD) struggle with low specificity when cell size differences are minimal.
• CTCs exhibit lower stiffness than leukocytes, offering an alternative sorting parameter.

Purpose of the Study:

• To develop a multistage microfluidic system for label-free, high-purity, and high-throughput sorting and analysis of CTCs.
• To improve CTC sorting specificity by integrating size-based and stiffness-based separation techniques.
• To enhance fluid regulation in DLD sorting using optimized microcolumn design.

Main Methods:

• A two-array DLD chip with droplet-shaped microcolumns (DMCs) was designed for initial size-based CTC sorting.
• A stiffness-based cone channel chip was developed to purify CTCs from contaminating leukocytes.
• Raman spectroscopy was employed for label-free cell type identification.
• Four DMC DLD chips were paralleled for high-throughput sample processing.

Main Results:

• The optimized DLD chip achieved a sample processing rate of 2.5 mL/min with 96.30 ± 2.10% recovery and 98.25 ± 2.48% purity.
• The cone channel chip improved CTC purity by 1.8-fold by entrapping leukocytes based on stiffness differences.
• The integrated system provided efficient, label-free CTC isolation and analysis.

Conclusions:

• The developed multistage microfluidic system offers a highly efficient and specific method for CTC isolation and analysis.
• Optimized DLD chips with DMCs significantly enhance fluid regulation and sorting performance.
• Combining size and stiffness-based sorting provides a robust approach for challenging CTC separation scenarios.