Recently, research on particle migration in non-Newtonian viscoelastic fluids has gained considerable attention. In a viscoelastic fluid, three dimensional (3D) particle focusing can be easily realized in simple channels without the need for any external force fields or complex microchannel structures compared with that in a Newtonian fluid. Due to its promising properties for particle precise focusing and manipulation, this field has been developed rapidly, and research on the field has been shifted from fundamentals to applications. This review will elaborate the recent progress of particle migration in viscoelastic fluids, especially on the aspect of applications. The hydrodynamic forces on the micro/nano particles in viscoelastic fluids are discussed. Next, we elaborate the basic particle migration in viscoelasticity-dominant fluids and elasto-inertial fluids in straight channels. After that, a comprehensive review on the applications of viscoelasticity-induced particle migration (particle separation, cell deformability measurement and alignment, particle solution exchange, rheometry-on-a-chip and others) is presented; finally, we thrash out some perspectives on the future directions of particle migration in viscoelastic fluids.

中文翻译：

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粘弹性流体中颗粒迁移的最新进展

最近，对非牛顿粘弹性流体中颗粒迁移的研究已引起广泛关注。在粘弹性流体中，与牛顿流体相比，可以在简单的通道中轻松实现三维（3D）粒子聚焦，而不需要任何外力场或复杂的微通道结构。由于其在粒子精确聚焦和操纵方面的广阔前景，该领域得到了迅速发展，并且该领域的研究已从基本原理转移到了应用领域。这篇综述将阐述粘弹性流体中颗粒迁移的最新进展，特别是在应用方面。讨论了粘弹性流体中微/纳米颗粒上的流体动力。下一个，我们阐述了在直通道中以粘弹性为主的流体和弹性惯性流体中的基本粒子迁移。之后，对粘弹性诱导的颗粒迁移的应用（颗粒分离，细胞可变形性测量和排列，颗粒溶液交换，芯片流变学等）的应用进行了全面综述；最后，我们对粘弹性流体中颗粒迁移的未来方向提出了一些看法。