Enhanced microfluidic multi-target separation by positive and negative magnetophoresis.

Area of Science:

• Microfluidics
• Biotechnology
• Biophysics

Background:

• Efficient sorting of biological targets is crucial for diagnostics and research.
• Existing microfluidic sorting methods face challenges in throughput and accuracy.
• Magnetophoresis offers a promising label-based and label-free approach for particle manipulation.

Purpose of the Study:

• To develop and validate a novel magnetophoresis-based microfluidic system for biological target sorting.
• To investigate the performance of positive magnetophoresis (pM) and negative magnetophoresis (nM) configurations.
• To analyze the impact of magnetic field gradients, hydrodynamics, and particle properties on separation efficiency.

Main Methods:

• Introduction of a single, externally magnetized ferromagnetic wire to induce repulsive magnetophoretic forces.
• Analysis of two transverse dual-mode magnetic configurations: single-magnet arrangement (SMA) and dual-magnet arrangement (DMA).
• Numerical simulations and experimental validation using soft lithography and 3D printing, employing N52 permanent magnets.

Main Results:

• The dual-magnet arrangement (DMA) demonstrated higher magnetic gradient generation and throughput for pM sorting of labeled particles.
• The single-magnet arrangement (SMA) showed superior magnetic properties and throughput for nM sorting of unlabeled cells (RBCs, WBCs, PC3-9).
• Both numerical and experimental results confirmed 100% separation accuracy across various Reynolds numbers, with experimental validation at Re=3.

Conclusions:

• The developed magnetophoresis-based microfluidic device enables highly accurate and efficient sorting of biological targets.
• The system's design, including wire movement and channel depth, allows for customization and increased throughput.
• This technology holds potential for automated biological sample handling and advanced diagnostic applications.