Abdel Fattah Abdel Rahman, Ghosh Suvojit, Puri Ishwar K
Department of Mechanical Engineering, McMaster University, Hamilton, Ontario, Canada.
Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada.
J Chromatogr B Analyt Technol Biomed Life Sci. 2016 Aug 1;1027:194-9. doi: 10.1016/j.jchromb.2016.05.046. Epub 2016 Jun 1.
Microfluidics has advanced magnetic blood fractionation by making integrated miniature devices possible. A ferromagnetic microstructure array that is integrated with a microfluidic channel rearranges an applied magnetic field to create a high gradient magnetic field (HGMF). By leveraging the differential magnetic susceptibilities of cell types contained in a host medium, such as paramagnetic red blood cells (RBCs) and diamagnetic white blood cells (WBCs), the resulting HGMF can be used to continuously separate them without attaching additional labels, such as magnetic beads, to them. We describe the effect of these ferromagnetic microstructure geometries have on the blood separation efficacy by numerically simulating the influence of microstructure height and pitch on the HGMF characteristics and resulting RBC separation. Visualizations of RBC trajectories provide insight into how arrays can be optimized to best separate these cells from a host fluid. Periodic microstructures are shown to moderate the applied field due to magnetic interference between the adjacent teeth of an array. Since continuous microstructures do not similarly weaken the resultant HGMF, they facilitate significantly higher RBC separation. Nevertheless, periodic arrays are more appropriate for relatively deep microchannels since, unlike continuous microstructures, their separation effectiveness is independent of depth. The results are relevant to the design of microfluidic devices that leverage HGMFs to fractionate blood by separating RBCs and WBCs.
微流控技术通过实现集成微型设备推动了磁性血液分离技术的发展。与微流控通道集成的铁磁微结构阵列能够重新排列施加的磁场，以产生高梯度磁场（HGMF）。通过利用主体介质中所含细胞类型的不同磁敏感性，如顺磁性红细胞（RBC）和抗磁性白细胞（WBC），所产生的高梯度磁场可用于连续分离它们，而无需给它们附加额外的标记，如磁珠。我们通过数值模拟微结构高度和间距对高梯度磁场特性及红细胞分离效果的影响，来描述这些铁磁微结构几何形状对血液分离效果的作用。红细胞轨迹的可视化展示为如何优化阵列以从主体流体中最佳分离这些细胞提供了见解。由于阵列相邻齿之间的磁干扰，周期性微结构会使施加的磁场减弱。由于连续微结构不会类似地削弱所产生的高梯度磁场，它们有助于实现显著更高的红细胞分离率。然而，周期性阵列更适合相对较深的微通道，因为与连续微结构不同，它们的分离效果与深度无关。这些结果与利用高梯度磁场通过分离红细胞和白细胞来进行血液分离的微流控设备设计相关。
