University of Michigan, Ann Arbor, MI, USA.
Biomed Microdevices. 2011 Feb;13(1):97-105. doi: 10.1007/s10544-010-9474-6.
A simple passive microfluidic device that continuously separates microparticles is presented. Its development is motivated by the need for specific size micro perfluorocarbon (PFC) droplets to be used for a novel gas embolotherapy method. The device consists of a rectangular channel in which inertial lift forces are utilized to separate particles in lateral distance. At the entrance of the channel, particles are introduced at the center by focusing the flow from a center channel with flow from two side channels. Downstream, large particles will occupy a lateral equilibrium position in shorter axial distance than small particles. At the exit of the channel, flow containing large particles is separated from flow containing small particles. It is shown that 10.2-μm diameter microspheres can be separated from 3.0-μm diameter microspheres with a separation efficiency of 69-78% and a throughput in the order of 2 ·10⁴ particles per minute. Computational Fluid Dynamics (CFD) calculations were done to calculate flow fields and verify theoretical particle trajectories. Theory underlying this research shows that higher separation efficiencies for very specific diameter cut-off are possible. This microfluidic channel design has a simple structure and can operate without external forces which makes it feasible for lab-on-a-chip (LOC) applications.
本文提出了一种简单的被动式微流控装置，可连续分离微颗粒。其发展的动机是需要特定大小的全氟碳（PFC）微液滴用于一种新型的气体栓塞疗法。该装置由一个矩形通道组成，其中利用惯性升力将颗粒在横向距离上分离。在通道的入口处，通过将中心通道的流动聚焦到两个侧通道的流动中，将颗粒引入中心。在下游，大颗粒在比小颗粒短的轴向距离上占据横向平衡位置。在通道的出口处，将含有大颗粒的流动与含有小颗粒的流动分离。结果表明，10.2μm 直径的微球可以与 3.0μm 直径的微球分离，分离效率为 69-78%，每分钟通过量约为 2×10^4 个颗粒。进行了计算流体动力学（CFD）计算，以计算流场并验证理论颗粒轨迹。该研究的理论基础表明，对于非常特定的直径截止值，可以实现更高的分离效率。这种微流道设计结构简单，无需外部力即可运行，因此适用于片上实验室（LOC）应用。
