IEEE Trans Biomed Eng. 2020 Feb;67(2):372-378. doi: 10.1109/TBME.2019.2913670. Epub 2019 Apr 29.
Negative magnetophoresis is a novel and attractive method for continuous microparticle sorting inside a magnetic medium. In this method, diamagnetic particles are sorted based on their sizes using magnetic buoyancy force and without any labeling process. Although this method provides some attractive features, such as low-cost fabrication and ease of operation, there are some obstacles that adversely affect its performance, especially for biological applications. Most types of magnetic media, such as ferrofluids, are not biocompatible, and the time-consuming process of sample preparation can be threatening to the viability of the cells within the sample. Furthermore, in this method, both the target and non-target particles are affected by the magnetic field, and therefore, a high separation efficiency cannot be achieved. In this paper, to isolate the abnormal cells from the other blood cells, a microfluidic device was designed using numerical simulation. This model utilizes negative magnetophoresis on a rotating disk, and to reduce the exposure time of the cells inside the magnetic medium, a micromixer is embedded in the upstream of the separator which rapidly prepares the sample. In this part, diluted blood sample and ferrofluid are mixed together utilizing magnetic force. Afterward, the separator sorts the cells into multiple outlets using magnetic buoyancy force as well as centrifugal force. The numerical procedure employed in this study shows that the proposed model is able to recover ∼100% of the abnormal cells from a particular outlet for binary and ternary separation of the cells with high throughputs. Although this percentage of separation may be lower in reality, the optimization of the proposed design by the numerical method can avoid trial-and-error during costly and time-consuming experiments. Also, the device proposed in this study reduces the exposure time of the cells inside the ferrofluid to just a few seconds, which can improve cell viability.
负磁泳是一种新颖且有吸引力的方法，可用于在磁性介质中连续对微颗粒进行分选。在这种方法中，顺磁颗粒根据其尺寸利用磁浮力进行分选，而无需任何标记过程。尽管该方法具有一些吸引人的特点，如低成本制造和易于操作，但也存在一些障碍会对其性能产生不利影响，特别是对于生物应用。大多数类型的磁性介质，如铁磁流体，都不是生物相容的，而且样品制备过程耗时，可能会威胁到样品中细胞的活力。此外，在这种方法中，目标和非目标颗粒都受到磁场的影响，因此无法实现高分离效率。在本文中，为了从其他血细胞中分离异常细胞，设计了一种使用数值模拟的微流控装置。该模型利用旋转磁盘上的负磁泳，为了减少磁性介质中细胞的暴露时间，在分离器的上游嵌入了一个微混合器，可快速制备样品。在这一部分，利用磁力将稀释的血液样本和铁磁流体混合在一起。然后，分离器利用磁浮力和离心力将细胞分成多个出口。本研究中采用的数值程序表明，所提出的模型能够从特定出口回收 100%的异常细胞，用于二元和三元细胞的高吞吐量分离。尽管在实际应用中，这种分离百分比可能会更低，但通过数值方法对所提出的设计进行优化可以避免在昂贵且耗时的实验中进行反复试验。此外，本研究中提出的装置将细胞在铁磁流体中的暴露时间缩短至仅几秒钟，这可以提高细胞活力。
