L形截面螺旋微流道中微粒的惯性聚焦特性  

Particle Inertial Focusing Characteristics in Spiral Microchannel with L-Shaped Cross-Section

作　　者：刘尧 张鑫杰 朱行杰 陈亚伟 韩帅 Liu Yao;Zhang Xinjie;Zhu Hangjie;Chen Yawei;Han Shuai(College of Mechanical and Electrical Engineering,Hohai University,Changzhou 213022,China)

机构地区：[1]河海大学机电工程学院,江苏常州213022

出　　处：《微纳电子技术》2022年第11期1184-1190,1210,共8页Micronanoelectronic Technology

基　　金：国家自然科学基金资助项目(51905150);中央高校基本科研业务费资助项目(B220202024);江苏省博士后科研资助计划项目(2019K033)。

摘　　要：研制了一种L形截面螺旋微流道结构的惯性微流控芯片,并基于数值模拟和实验测试的方法研究了粒径6μm的聚苯乙烯粒子在微流道中的惯性聚焦效应。通过分析粒子运动轨迹的荧光图谱和对应的荧光强度曲线,发现随着粒子溶液体积流量增加至200μL/min及以上时,绝大部分粒子逐渐聚焦至微流道内壁面附近的平衡位置,形成宽约18μm的粒子聚焦带。此外,发现该微流道存在800μL/min的体积流量阈值,当粒子溶液体积流量超过阈值时,部分粒子会聚焦至靠近微流道中心处的平衡位置,从而形成另一束宽约9μm的粒子聚焦带。进一步研究粒子的双聚焦平衡位置沿螺旋微流道长度的变化规律,发现起初两束粒子聚焦带分别位于内外两侧矩形微流道中,此后会随运动距离的增加逐渐变窄,并向微流道内侧迁移,尤其当粒子运动至流道第8圈时,外侧矩形微流道的粒子将被内侧强二次流漩涡逐步拖拽至内侧微流道中,并被束缚于内壁面附近。上述研究结论可为深入研究复杂结构微流道中粒子的惯性聚焦机理提供重要参考。An inertial microfluidic chip of spiral microchannel with L-shaped cross-section was developed.Based on the methods of numerical simulation and experimental measurement,the inertial focusing effect of polystyrene particles with a particle size of 6μm in the microchannel was studied.By analyzing the fluorescence spectrum of the particle motion trajectory and the corresponding fluorescence intensity curves,it is found that most particles are focused to an equilib-rium position close to the inner wall of the mircochannel when the volume flow rate of the particle solution reaches 200μL/min and above,generating a particle focusing band with a width of around 18μm.Besides,it is found that when the volume flow rate of the particle solution exceeds a threshold value of 800μL/min of the mircochannel,some particles will be focused to an equilibrium position near the center of the microchannel,forming another particle focusing band with a width of around 9μm.The variation rule of the double-focused equilibrium positions of particles along the length of spiral microchannel was further studied.And it is found that initially the two particle focusing bands locate at the inside and outside of the rectangular microchannel respectively,and then the widths of the particle focusing bands gradually reduce and the two particle focusing bands transfer towards the inner side of the microchannel with the increase of the motion distance.Particularly as the particles move to the 8 th turn of the microchannel,the strong secondary flow vortex on the inner side will progressively drag the particles in the outside rectangular microchannel into the inner microchannel,and the particles will be trapped close to the inner wall surface.The above research results can provide a significant reference for further investigation of the particle inertial focusing mechanism in microchannels with complicated structures.

关 键 词：微流控芯片 螺旋微流道 L形截面 惯性聚焦效应 聚苯乙烯粒子 

分 类 号：O35[理学—流体力学]