Zhou Jian, Papautsky Ian
Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 USA.
Microsyst Nanoeng. 2020 Dec 14;6:113. doi: 10.1038/s41378-020-00218-x. eCollection 2020.
The manipulation of cells and particles suspended in viscoelastic fluids in microchannels has drawn increasing attention, in part due to the ability for single-stream three-dimensional focusing in simple channel geometries. Improvement in the understanding of non-Newtonian effects on particle dynamics has led to expanding exploration of focusing and sorting particles and cells using viscoelastic microfluidics. Multiple factors, such as the driving forces arising from fluid elasticity and inertia, the effect of fluid rheology, the physical properties of particles and cells, and channel geometry, actively interact and compete together to govern the intricate migration behavior of particles and cells in microchannels. Here, we review the viscoelastic fluid physics and the hydrodynamic forces in such flows and identify three pairs of competing forces/effects that collectively govern viscoelastic migration. We discuss migration dynamics, focusing positions, numerical simulations, and recent progress in viscoelastic microfluidic applications as well as the remaining challenges. Finally, we hope that an improved understanding of viscoelastic flows in microfluidics can lead to increased sophistication of microfluidic platforms in clinical diagnostics and biomedical research.
微通道中悬浮于粘弹性流体中的细胞和颗粒的操控已引起越来越多的关注，部分原因是其能够在简单的通道几何结构中实现单流三维聚焦。对非牛顿效应在颗粒动力学方面理解的改进，促使人们对利用粘弹性微流体进行颗粒和细胞的聚焦及分选展开了更广泛的探索。多种因素，如由流体弹性和惯性产生的驱动力、流体流变学的影响、颗粒和细胞的物理性质以及通道几何结构等，相互作用并共同竞争，从而决定了颗粒和细胞在微通道中复杂的迁移行为。在此，我们回顾了此类流动中的粘弹性流体物理学和流体动力，并确定了共同决定粘弹性迁移的三对相互竞争的力/效应。我们讨论了迁移动力学、聚焦位置、数值模拟以及粘弹性微流体应用的最新进展以及尚存的挑战。最后，我们希望对微流体中粘弹性流动的更深入理解能够使微流体平台在临床诊断和生物医学研究中更加精密复杂。
