Controlling acoustic streaming in an ultrasonic heptagonal tweezers with application to cell manipulation

Bernassau, A.L., Glynne-Jones, P., Gesellchen, F., Riehle, M. , Hill, M. and Cumming, D.R.S. (2014) Controlling acoustic streaming in an ultrasonic heptagonal tweezers with application to cell manipulation. Ultrasonics, 54(1), pp. 268-274. (doi:10.1016/j.ultras.2013.04.019)

Bernassau, A.L., Glynne-Jones, P., Gesellchen, F., Riehle, M. , Hill, M. and Cumming, D.R.S. (2014) Controlling acoustic streaming in an ultrasonic heptagonal tweezers with application to cell manipulation. Ultrasonics, 54(1), pp. 268-274. (doi:10.1016/j.ultras.2013.04.019)

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Publisher's URL: http://dx.doi.org/10.1016/j.ultras.2013.04.019

Abstract

Acoustic radiation force has been demonstrated as a method for manipulating micron-scale particles, but is frequently affected by unwanted streaming. In this paper the streaming in a multi-transducer quasi-standing wave acoustic particle manipulation device is assessed, and found to be dominated by a form of Eckart streaming. The experimentally observed streaming takes the form of two main vortices that have their highest velocity in the region where the standing wave is established. A finite element model is developed that agrees well with experimental results, and shows that the Reynolds stresses that give rise to the fluid motion are strongest in the high velocity region. A technical solution to reduce the streaming is explored that entails the introduction of a biocompatible agar gel layer at the bottom of the chamber so as to reduce the fluid depth and volume. By this means, we reduce the region of fluid that experiences the Reynolds stresses; the viscous drag per unit volume of fluid is also increased. Particle Image Velocimetry data is used to observe the streaming as a function of agar-modified cavity depth. It was found that, in an optimised structure, Eckart streaming could be reduced to negligible levels so that we could make a sonotweezers device with a large working area of up to 13 mm × 13 mm.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cumming, Professor David and Bernassau, Dr Anne and Riehle, Dr Mathis and Gesellchen, Dr Frank
Authors: Bernassau, A.L., Glynne-Jones, P., Gesellchen, F., Riehle, M., Hill, M., and Cumming, D.R.S.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Ultrasonics
ISSN:0041-624X
Published Online:15 May 2013

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