Department of Mechanical Engineering, University of Louisville, Louisville, KY 40208, USA.
Lab Chip. 2012 Apr 7;12(7):1296-301. doi: 10.1039/c2lc21034g. Epub 2012 Feb 16.
A new microfluidics technique that exploits the selectivity of phase partitioning and high-speed focusing capabilities of the inertial effects in flow was developed for continuous label-free sorting of particles and cells. Separations were accomplished by introducing particles at the interface of polyethylene glycol (PEG) and dextran (DEX) phases in rectangular high aspect-ratio microfluidic channels and allowing them to partition to energetically favorable locations within the PEG phase, DEX phase or interface at the center of the microchannel. Separation of partitioned particles was further enhanced via inertial lift forces that develop in high aspect-ratio microchannels that move particles to equilibrium positions close to the outer wall. Combining phase partitioning with inertial focusing ensures selectivity is possible using phase partitioning with sufficient throughput (at least an order of magnitude greater than phase partitioning alone) for application in the clinical and research setting. Using this system we accomplished separation of 15 μm polystyrene (PS) particles from 1-20 μm polymethylmethacrylate (PMMA) particles. Results confirm the feasibility of separation based on phase partitioning and enhancement of separation via inertial focusing. Approximately 86% of PS particles were isolated within the PEG phase whereas 78% of PMMA particles were isolated within the DEX phase. When a binary mixture of PS and PMMA was introduced within the device, ~83% of PS particles were isolated in the PEG phase and ~74% of PMMA particles were isolated in the DEX phase. These results confirm the feasibility of this technique for rapid and reliable separation of particles and potentially cells.
一种新的微流控技术，利用相分离的选择性和惯性效应的高速聚焦能力，开发用于连续的无标记粒子和细胞分选。通过在矩形高纵横比微流控通道中的聚乙二醇 (PEG) 和葡聚糖 (DEX) 相的界面处引入粒子，并允许它们在 PEG 相中、DEX 相或微通道中心的界面处分配到能量有利的位置，来实现分离。通过在高纵横比微通道中产生的惯性升力进一步增强分离效果，这些升力将粒子移动到靠近外壁的平衡位置。将相分离与惯性聚焦相结合，可确保使用相分离具有足够的吞吐量（至少比相分离本身高出一个数量级）来实现临床和研究应用的选择性。使用该系统，我们实现了从 15μm 聚苯乙烯 (PS) 粒子到 1-20μm 聚甲基丙烯酸甲酯 (PMMA) 粒子的分离。结果证实了基于相分离的分离的可行性，并通过惯性聚焦增强了分离效果。大约 86%的 PS 粒子被隔离在 PEG 相中，而大约 78%的 PMMA 粒子被隔离在 DEX 相中。当在设备中引入 PS 和 PMMA 的二元混合物时，大约 83%的 PS 粒子被隔离在 PEG 相中，而大约 74%的 PMMA 粒子被隔离在 DEX 相中。这些结果证实了该技术用于快速可靠地分离粒子和潜在细胞的可行性。
