Feng Haidong, Patel Dhruv, Magda Jules J, Geher Sage, Sigala Paul A, Gale Bruce K
Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah84112, United States.
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States.
ACS Omega. 2022 Nov 2;7(45):41759-41767. doi: 10.1021/acsomega.2c06021. eCollection 2022 Nov 15.
Viscoelastic flow has been widely used in microfluidic particle separation processes, in which particles get focused on the channel center in diluted viscoelastic flow. In this paper, the transition from single-stream focusing to multiple-streams focusing (MSF) in high viscoelastic flow is observed, which is applied for cell separation processes. Particle focusing stream bifurcation is caused by the balance between elastic force and viscoelastic secondary flow drag force. The influence of cell physical properties, such as cell dimension, shape, and deformability, on the formation of multiple-streams focusing is studied in detail. Particle separation is realized utilizing different separation criteria. The size-based separation of red (RBC) and white (WBC) blood cells is demonstrated in which cells get focused in different streams based on their dimension difference. Cells with different deformabilities get stretched in the viscoelastic flow, leading to the change of focusing streams, and this property is harnessed to separate red blood cells infected with the malaria parasite, . The achieved results promote our understanding of particle movement in the high viscoelastic flow and enable new particle manipulation and separation processes for sample treatment in biofluids.
粘弹性流动已广泛应用于微流控颗粒分离过程，在该过程中，颗粒在稀释的粘弹性流体中聚焦于通道中心。本文观察到在高粘弹性流体中从单流聚焦到多流聚焦（MSF）的转变，并将其应用于细胞分离过程。颗粒聚焦流的分叉是由弹力和粘弹性二次流拖曳力之间的平衡引起的。详细研究了细胞物理特性，如细胞尺寸、形状和可变形性，对多流聚焦形成的影响。利用不同的分离标准实现颗粒分离。展示了基于大小的红细胞（RBC）和白细胞（WBC）分离，其中细胞根据其尺寸差异聚焦于不同的流中。具有不同可变形性的细胞在粘弹性流体中被拉伸，导致聚焦流的变化，利用这一特性可分离感染疟原虫的红细胞。所取得的结果增进了我们对高粘弹性流体中颗粒运动的理解，并为生物流体中的样品处理实现了新的颗粒操纵和分离过程。
