top of page

Characterization Of Acoustofluidic Geometric Traps By Means Of Defocus Particle Tracking

M. Rossi, J. H. Joergensen, H. Bruus

Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark

In this work we used the General Defocusing Particle Tracking method to measure the three-dimensional trajectories of 10-μm-diameter polystyrene beads moving inside a micro-acoustofluidic device. The aim is to measure the change in acoustic energy density induced by localized modifications of the channel geometry. The measurements were performed in a glass capillary tube with a rectangular cross-section of 2.0 mm × 0.2 mm. The wall thickness of the capillary tube is 140 μm and it was locally increased by gluing a glass slide with a thickness of 100 μm. The acoustic energies at five different frequencies around the expected resonant frequency have been estimated for the single-glass and double-glass region from the measured particle paths. The results showed a down-shift of the resonant frequency in the double-glass zone, as expected from theoretical predictions. This approach can be used to create multiple acoustofluidic traps based on simple geometrical modifications of the microchannel.

20th Edition
bottom of page