各种微纳尺度颗粒、细胞、细菌等的精确操控在众多研究和应用领域中具有重要价值。基于微尺度粘弹性效应的颗粒操控方法是近几年出现的一类微流控新方法。相比牛顿流体，它拥有更灵活的操控优势和更广泛的应用前景。此类器件的成功应用有赖于对微尺度粘弹性流体中颗粒输运现象的系统认识，然而，鉴于粘弹性流体的复杂流变特性，相关研究非常有限。本项目拟结合实验观测和三维数值模拟，探索流体流变性质、通道几何形状、流动参数等对颗粒运动规律的影响，增强对粘弹性微流控器件中颗粒操控的深入了解和精确预测。在调控优化粘弹性流体流变性质的基础上，结合惯性效应，实现不同尺寸颗粒和细胞的汇聚、捕捉、富集、分选等功能，并进一步将研究拓展至纳米尺度颗粒和非球形颗粒的操控。通过建立相关流动和颗粒运动规律，发展结合微流动粘弹性效应和惯性效应优势的无标记颗粒高通量操控新技术。

Precise manipulation of various micro/nano-particles, cell, and bacteria is of great importance in many research and application areas. Very recently, particle manipulation based on microscale viscoelastic effects becomes an emerging microfluidic technique. Compared to the Newtonian fluids, it shows more flexible advantages and more extensive applications. The thorough understanding of the particle transportation in viscoelastic fluids is necessary for the successful implement of this type of microfluidic devices. Due to the complex rheological properties of viscoelastic fluids, however, the existing research is very limited. We will integrate experimental observations and 3-D numerical simulations to investigate the effects on the particle migration by rheological properties of fluids, microchannel geometries, and flow conditions, advancing our understanding and prediction of particle manipulation in viscoelastic microdevices. By optimizing the rheological properties of viscoelastic fluids and utilizing inertial effects , we aim to realize better focusing, trapping, concentration, and sorting of particles and cells with various sizes. The study will be further extended to manipulation of nano-particles and non-spherical particles. The acquired knowledge will build the fluid mechanics and particle transport foundations, with the goals of developing a new high-throughput technology for label-free cell handling based on mirofluidic viscoelastic and inertial effects.