超声操控薄膜近场微纳颗粒的声泳行为研究

Precise manipulation of cells or microscale objects is a critical step for many biomedical and chemical applications. It has been demonstrated in recently years that ultrasound can be applied to noncontact manipulate almost any kind of particles and is nearly harmless to the exposed particles. Based on related results, this research studies acoustophoresis of sphere microparticles in liquids over thin membranes under ultrasonic excitations, including theoretical solutions of acoustophoresis and trajectories of microparticles, the modelling of acoustophoresis of a single particle and a cluster of particles for the design of microfluidic particle manipulation devices, and experimental measurements of microparticle acoustophoresis and the verification of Chladni and inverse Chladni patterns and their formation conditions. This project aims at investigating the effects of many key factors, such as ultrasonic excitations, materials and sizes of thin membranes, and fluid properties, on the microparticle acoustophoresis over vibrating thin membranes...The results of this research can provide theoretical basis and guidance for the design of thin membrane-based acousto-microfluidic devices for precise manipulation of cells or other microscale objects. Moreover, it can also provide effective and efficient means for settling many problems to be solved in the field of micro-acoustofluidics, such as microfluidic particle-particle, particle-substrate interactions and so forth.

对细胞或微尺度物体进行精确操控是实现生物医学、化学等领域诸多应用的关键步骤。近年来实验上已证明超声可以用于非接触、无损伤地操控几乎任何种类的颗粒。本项目申请者在已有相关研究成果基础上，拟对超声驱动下，微型薄膜上液体介质中各尺度微纳米球形颗粒的声泳行为进行深入研究：从理论上求解微纳颗粒的声泳行为及运动轨迹曲线；对微纳颗粒的声泳行为进行数值模拟；实验测量微纳颗粒的声泳行为，验证Chladni和逆Chladni图形及其形成条件。项目旨在系统研究超声场（频率、强度等）、薄膜属性（密度、杨氏模量、泊松比、各向尺寸等）、介质属性（密度、粘度等）等关键参数对微型薄膜振动系统微纳米颗粒动力学行为的影响。该项目的研究成果将为基于微型薄膜的超声微纳操控装置的设计提供理论依据和实验指导。同时它也将为研究超声微流控领域很多待解决的问题提供有效方法，比如超声微流体环境里颗粒与颗粒、颗粒与载体的相互作用研究等。

声微流控，即利用声流体效应操控微通道内的流体和微纳尺度颗粒（如细胞、病毒等），在物理、化学、生物医学等领域发挥着重要的作用。本项目从理论和实验上研究了多种超声作用下的声流体效应以及微纳颗粒的声动力学行为。首先研究了振动薄膜近场的声流体效应，建立和优化了求解振动平板近场声流体效应和微纳颗粒三维声动力学行为的理论和数值模型；其次研究了超声驱动下单层微囊泡内的声流体效应，理论和实验发现了超声不仅可以操控微纳尺度颗粒，还能驱动微囊泡内的液体定向移动；然后研究了声子晶体共振引起的声流体效应，理论发现了超快速瑞利声流及其驱动下微纳尺度颗粒的超快速声动力学行为；最后还研究了外方内圆异形截面微流控芯片内的声流体效应，并实现了微尺度颗粒的超声快速二维聚集、排列及其高效显微成像。本项目的研究不仅呈现了超声作用下声流体效应的多样性，实现了宽范围、多形式的超声颗粒操控，还为异形微流控芯片在超声微纳尺度颗粒操控上的广阔应用提供了理论支撑和实验依据。