Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cell Biology

Background:

• Leukocyte counts are vital biomarkers for disease diagnosis and potential cell-based immunotherapies.
• Isolating leukocytes from whole blood is challenging due to their low abundance relative to erythrocytes.
• Existing methods often require complex procedures for effective leukocyte retrieval.

Purpose of the Study:

• To develop a single-step microfluidic platform for isolating and recovering leukocytes from diluted whole blood.
• To optimize separation parameters for high efficiency, purity, and cell viability.
• To enable portable, near-patient testing applications.

Main Methods:

• A sheathless microfluidic device employing deterministic lateral displacement (DLD) for cell separation.
• Blood cells are focused into a dense stream using a novel tubing-based sedimentation and hexagonal inlet structure.
• Evaluation of focusing structures, tubing-chip interface, hematocrit, and flow rate effects on separation.

Main Results:

• Achieved 100% separation efficiency, 76% recovery rate, and 80% purity for leukocytes from diluted blood.
• Maintained high cell viability (98%) during the isolation process.
• Demonstrated stable operation for over 30 minutes at a flow rate of 2 μL/min.

Conclusions:

• The developed microfluidic platform effectively isolates leukocytes in a single step with high purity and viability.
• The platform's portability, enhanced by a handheld pressure controller, facilitates near-patient testing.
• This technology is suitable for integration with downstream diagnostic and cell-based assays.