A glass microfluidic chip for continuous blood cell sorting by a magnetic gradient without labeling

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cell Separation

Background:

• Efficient separation of red blood cells (RBCs) from whole blood is crucial for various diagnostic and research applications.
• Existing methods often face challenges with efficiency, throughput, or cell viability.

Purpose of the Study:

• To develop and demonstrate a microfluidic chip for highly efficient RBC separation based on their intrinsic magnetic properties.
• To optimize the chip design and operating parameters for maximum RBC recovery.

Main Methods:

• Fabrication of a glass microfluidic chip using photolithography and thermal bonding.
• Integration of a nickel wire within the separation channel to generate a magnetic gradient.
• Application of an external permanent magnet (0.3 T) to induce magnetic forces on RBCs.
• Optimization of flow rates (0.12-0.92 microL/min) and use of bovine serum albumin to mitigate cell sedimentation.

Main Results:

• Continuous separation of RBCs from diluted whole blood samples.
• Achieved up to 93.7% RBC recovery in the middle outlet at a flow rate of 0.23 microL/min.
• Demonstrated successful visual tracking of the separation process using quantum dot labeling.

Conclusions:

• The developed microfluidic chip provides a highly efficient method for RBC separation using native magnetic properties.
• The technology shows potential for applications in blood analysis, diagnostics, and cell research.
• Further investigation into cell distribution phenomena around the magnetic field source is warranted.