US-UK Cooperative Research: Manipulation and Separation of Biological Particles and Cells by Ultrasonic Forces and Torques

该奖项将支持米德尔伯里学院的Robert Gould博士和加的夫威尔士大学的W. Terence Coakley博士在生物物理学方面的合作研究。该项目的目的是利用超声波来分离和分离具有生物学意义的大颗粒。当超声驻波场存在于充满液体的腔室中时，给定类型的悬浮粒子将倾向于在腔室中相距约半波长的位置聚集。与驻波场相关的辐射压力和声流的超声波现象对悬浮物体产生力和扭矩。作用在给定粒子上的力和扭矩的强度主要取决于粒子的大小和形状，以及相对于悬浮液体的相应性质的粒子的可压缩性和密度的声学性质。因此，声学特性不同的粒子将倾向于在腔室的不同位置聚集。大多数生物学家熟悉的悬浮颗粒收集方法，如离心、介电泳和应用磁场，往往会导致颗粒迁移到一个或两个位置。超声提供了一种独特的能力，可以在悬浮阶段的许多离散位置集中颗粒。这个项目的目的是利用不同类型的粒子在力和扭矩上的差异来区分它们，一种类型与另一种类型，这样它们就可以被单独收集和研究。这项研究的结果将为超声波在各种生物系统中的适用性提供重要信息。该项目将受益于两位研究人员的互补专业知识，以及他们过去富有成效的合作历史。

This award will support collaborative research in biophysics between Dr. Robert Gould, Middlebury College and Dr. W. Terence Coakley, University of Wales, Cardiff. The objective of the project is to exploit the use of ultrasound to segregate and isolate large particles of biological interest. When an ultrasonic standing wave field exists in a liquid-filled chamber, suspended particles of a given type will tend to collect at positions in the chamber about a half wavelength apart. The ultrasonic phenomena of radiation pressure and acoustic streaming associated with a standing wave field produce forces and torques on objects in suspension. Strengths of the forces and torques on a given particle depend mainly on the size and shape of the particle and on the acoustical properties of compressibility and density of the particle, relative to the corresponding properties of the suspending liquid. Thus particles differing in acoustic properties will tend to collect in different positions in the chamber. Methods for collecting particles in suspension with which most biologists are familiar, such as centrifugation, dielectrophoresis and application of magnetic fields, tend to cause particles to migrate to one or two sites. Ultrasound offers a unique capability to concentrate particles at many discrete locations in the suspending phase. This project aims to utilize the differences in the forces and torques on different types of particles to diverge them, one type from another, so they may be harvested and studied separately. The results of this research will provide important information regarding the applicability of ultrasound to a variety of biological systems. The project will benefit from the complementary expertise of the two investigators, as well as their past history of fruitful collaboration.