Continuous inertial focusing, ordering, and separation of particles in microchannels
Continuous inertial focusing, ordering, and separation of particles in microchannels
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DOI：
10.1073/pnas.0704958104
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发表时间：
2007-11-27
影响因子：
11.1
通讯作者：
Toner, Mehmet
中科院分区：
文献类型：
--
作者：
Di Carlo, Dino;Irimia, Daniel;Toner, Mehmet
在层流条件下，当没有外力作用时，颗粒通常被认为遵循流体流线。与这种观点相反，我们观察到，在经历层流流动的微通道中，流动的颗粒以连续、可预测和准确的方式跨越流线迁移。这种迁移归因于当流动的惯性方面变得重要时观察到的对颗粒的升力。我们确定了对称和不对称的通道几何结构，它们提供了额外的惯性力，偏向特定的平衡位置，以产生连续的有序粒子流，这些粒子流精确地定位在三个空间维度上。我们能够在通道的横向平面内，以>；80纳米的精度对颗粒进行横向排序，并在纵向上，沿着流动方向以规则的链条排列。观察到盘状红细胞的第四维旋转排列。出乎意料的是，有序性似乎与粒子的浮力方向无关，这表明只有很小的离心力贡献。理论分析表明，物理原理在一定范围的通道和粒子长度范围内是可行的。这种在微通道中连续、高速率、无外力地对不同大小的颗粒进行差异化排序的能力有望在连续生物微粒分离、高通量细胞术和大规模过滤系统中有广泛的应用。
Under laminar flow conditions, when no external forces are applied, particles are generally thought to follow fluid streamlines. Contrary to this perspective, we observe that flowing particles migrate across streamlines in a continuous, predictable, and accurate manner in microchannels experiencing laminar flows. The migration is attributed to lift forces on particles that are observed when inertial aspects of the flow become significant. We identified symmetric and asymmetric channel geometries that provide additional inertial forces that bias particular equilibrium positions to create continuous streams of ordered particles precisely positioned in three spatial dimensions. We were able to order particles laterally, within the transverse plane of the channel, with > 80-nm accuracy, and longitudinally, in regular chains along the direction of flow. A fourth dimension of rotational alignment was observed for discoidal red blood cells. Unexpectedly, ordering appears to be independent of particle buoyant direction, suggesting only minor centrifugal contributions. Theoretical analysis indicates the physical principles are operational over a range of channel and particle length scales. The ability to differentially order particles of different sizes, continuously, at high rates, and without external forces in microchannels is expected to have a broad range of applications in continuous bioparticle separation, high-throughput cytometry, and large-scale filtration systems.