Fundamentals of elasto-inertial particle focusing in curved microfluidic channels
Fundamentals of elasto-inertial particle focusing in curved microfluidic channels
复制标题
弯曲微流体通道中弹惯性粒子聚焦的基础知识
DOI：
10.1039/c6lc00376a
复制
发表时间：
2016-01-01
期刊：
影响因子：
6.1
通讯作者：
Ni, Zhonghua
中科院分区：
文献类型：
--
作者：
Xiang, Nan;Zhang, Xinjie;Ni, Zhonghua
粘弹性流体中的弹性惯性聚焦由于其在颗粒计数和分选中的潜在应用，近年来引起了人们越来越多的兴趣。然而，目前对弹性惯性聚焦机理的研究主要集中在简单的直流道上，对弯曲流道的研究较少。在此，我们通过实验研究了螺旋微流控通道中颗粒在不同流速、通道纵横比和通道半径范围内的弹性惯性聚焦行为。与没有粘弹性的惯性微流体相比，由于弹性、惯性和Dean流的复杂耦合，我们的螺旋弹性-惯性微流体系统中的粒子聚焦模式表现出更有趣的方式。在获得数据的基础上，分析了聚焦行为背后的潜在机理和力竞争。此外，我们还首次提出了一个六阶段过程模型来描述Dean耦合弹性惯性流中随流量增加的粒子聚焦过程。有趣的是，只有在高流速下，Dean阻力才对颗粒聚焦有显著贡献，并最终将颗粒聚焦位置移到外流道区域。通过仔细平衡作用在粒子上的力，也可以在类似于百亩L分钟(-1)的吞吐量水平上实现单线3D聚焦，这远远高于大多数现有研究中的水平。我们预计，这种对粒子聚焦机制的更好理解将为螺旋弹性惯性微流控系统的设计和操作提供有用的见解。
Elasto-inertial focusing in viscoelastic fluids has attracted increasing interest in recent years due to its potential applications in particle counting and sorting. However, current investigations of the elasto-inertial focusing mechanisms have mainly been focused on simple straight channels with little attention being paid to curved channels. Herein, we experimentally explore the elasto-inertial focusing behaviors of particles in spiral microfluidic channels over a wide range of flow rates, channel aspect ratios and channel radii. As compared with those observed in inertial microfluidics without viscoelasticity, the particle focusing pattern in our spiral elasto-inertial microfluidic system appears in a more interesting manner due to the complex coupling of elasticity, inertia and Dean flow effects. On the basis of the obtained data, the underlying mechanics and force competition behind the focusing behaviors are analyzed. In addition, for the first time, we propose a six-stage process model illustrating the particle focusing process in Dean-coupled elasto-inertial flows with increasing flow rate. It is interesting to find that the Dean drag force makes a significant contribution to particle focusing only at high flow rates and finally shifts the particle focusing positions into the outer channel region. Through carefully balancing the forces acting on particles, single-line 3D focusing can also be achieved at a throughput level of similar to 100 mu l min(-1), which is much higher than those in most existing studies. We envision that this improved understanding of the particle focusing mechanisms would provide helpful insights into the design and operation of spiral elasto-inertial microfluidic systems.