Continuous Flow Labeling and In-Line Magnetic Separation of Cells

Zhixi Qian,Paul Todd,Eugene D Boland,James F Leary,Lisa M Reece,Thomas R Hanley

doi:10.3390/magnetochemistry8010005

Abstract

There is an identified need for point-of-care diagnostic systems for detecting and counting specific rare types of circulating cells in blood. By adequately labeling such cells with immunomagnetic beads and quantum dots, they can be efficiently collected magnetically for quantification using fluorescence methods. Automation of this process requires adequate mixing of the labeling materials with blood samples. A static mixing device can be employed to improve cell labeling efficiency and eliminate error-prone laboratory operations. Computational fluid dynamics (CFD) were utilized to simulate the flow of a labeling-materials/blood mixture through a 20-stage in-line static mixer of the interfacial-surface-generator type. Optimal fluid mixing conditions were identified and tested in a magnetic bead/tumor cell model, and it was found that labeled cells could be produced at 1.0 mL/min flow rate and fed directly into an in-line magnetic trap. The trap design consists of a dual flow channel with three bends and a permanent magnet positioned at the outer curve of each bend. The capture of labeled cells in the device was simulated using CFD, finite-element analysis and magnetophoretic mobility distributions of labeled cells. Testing with cultured CRL14777 human melanoma cells labeled with anti-CD146 1.5 μm diameter beads indicated that 90 ± 10% are captured at the first stage, and these cells can be captured when present in whole blood. Both in-line devices were demonstrated to function separately and together as predicted.

Highlights

IntroductionEffective rare-target-cell capture and detection methods have been proven (reviewed by Labib, 2021 [1]) and commercialized, including the CellSearch platform [2], the only one approved by FDA to date for the enumeration of circulating tumor cells
Effective rare-target-cell capture and detection methods have been proven and commercialized, including the CellSearch platform [2], the only one approved by FDA to date for the enumeration of circulating tumor cells. This and most methods of rare cell enrichment utilize immunomagnetic labeling and magnetic capture of target cells; a number of microfluidic platforms capture target cells on antibody coated surfaces, while others rely on non-specific separations based on fluid dynamics
When 105 tumor cells were in the input, we found 90+% of the input tumor cells collected in the trap, and

Summary

Introduction

Effective rare-target-cell capture and detection methods have been proven (reviewed by Labib, 2021 [1]) and commercialized, including the CellSearch platform [2], the only one approved by FDA to date for the enumeration of circulating tumor cells. This and most methods of rare cell enrichment utilize immunomagnetic labeling and magnetic capture of target cells; a number of microfluidic platforms capture target cells on antibody coated surfaces, while others rely on non-specific separations based on fluid dynamics.

Methods

Results

Conclusion