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Suppression of acoustic streaming in liquids of inhomogeneous density and compressibility

Hajdarovic, Dzenan LU (2016) BMEM01 20162
Department of Biomedical Engineering
Abstract
This thesis provides strong evidence that acoustic streaming is suppressed when using liquids of inhomogeneous density and compressibility in acoustophoresis. Manipulation of extremely small particles in acoustophoresis is something that usually is impaired by acoustic streaming. The project was divided into three aims. Firstly, a particle tracking software (GDPT) was evaluated using 3 μm polystyrene beads letting them sediment inside of a microchannel. Then, the flow of 1 μm and 4.8 μm polystyrene beads was studied separately, influenced by an acoustic field. The obtained trajectories and velocities of these beads were then solved analytically with existing theory describing acoustophoretic particle motion. Lastly and most importantly,... (More)
This thesis provides strong evidence that acoustic streaming is suppressed when using liquids of inhomogeneous density and compressibility in acoustophoresis. Manipulation of extremely small particles in acoustophoresis is something that usually is impaired by acoustic streaming. The project was divided into three aims. Firstly, a particle tracking software (GDPT) was evaluated using 3 μm polystyrene beads letting them sediment inside of a microchannel. Then, the flow of 1 μm and 4.8 μm polystyrene beads was studied separately, influenced by an acoustic field. The obtained trajectories and velocities of these beads were then solved analytically with existing theory describing acoustophoretic particle motion. Lastly and most importantly, the acoustic streaming of 1 μm polystyrene beads was examined when laminating the particle-solution with a density gradient medium called iodixanol, following acoustic actuation. The evaluation of the GDPT-software and the particle trajectories and velocities were deemed as valid since they corresponded to theoretical expectations. Regarding the main goal of the project, it was found that when using inhomogeneous medium, the acoustic streaming would decrease by a factor of 57, in comparison to when homogeneous medium is used. The acoustic streaming is thus mainly influenced by the acoustic radiation force, giving a lateral motion of the polystyrene beads. Ultimately, these results indicate that it will be possible to manipulate and deal with particles as small as bacteria and viruses in acoustophoresis, giving a potential tool, globally speaking, in the fight against aggressive infections in today’s healthcare. (Less)
Popular Abstract (Swedish)
Hur man blir av med små mikroskopiska strömmar på nolltid

Bakterie- och virusinfektioner är i dagsläget ett stort problem inom sjukvården, mycket tack vare att dessa blir mer och mer motståndskraftiga mot läkemedel och vaccin. En metod vid namn akustofores ger snabba och skonsamma analyser av t.ex. blodprov. Begränsningen med denna metod relaterar till ett fenomen som kallas akustisk strömning. Detta arbete undersökte om denna cirkulära strömning kunde motverkas genom att använda vätskor med inhomogena egenskaper. Det visade sig att strömningen reducerades med en faktor 57 och därmed kan partiklar av samma storlek som bakterier manipuleras i ett akustiskt fält.
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author
Hajdarovic, Dzenan LU
supervisor
organization
course
BMEM01 20162
year
type
H2 - Master's Degree (Two Years)
subject
keywords
inhomogeneous medium, density gradients, acoustic streaming, iso-acoustic focusing, acoustophoresis, microchannel, microfluidics, general defocusing particle tracking, astigmatic particle tracking
language
English
additional info
2016-20
id
8895317
date added to LUP
2016-11-22 13:41:31
date last changed
2016-11-24 10:23:36
@misc{8895317,
  abstract     = {This thesis provides strong evidence that acoustic streaming is suppressed when using liquids of inhomogeneous density and compressibility in acoustophoresis. Manipulation of extremely small particles in acoustophoresis is something that usually is impaired by acoustic streaming. The project was divided into three aims. Firstly, a particle tracking software (GDPT) was evaluated using 3 μm polystyrene beads letting them sediment inside of a microchannel. Then, the flow of 1 μm and 4.8 μm polystyrene beads was studied separately, influenced by an acoustic field. The obtained trajectories and velocities of these beads were then solved analytically with existing theory describing acoustophoretic particle motion. Lastly and most importantly, the acoustic streaming of 1 μm polystyrene beads was examined when laminating the particle-solution with a density gradient medium called iodixanol, following acoustic actuation. The evaluation of the GDPT-software and the particle trajectories and velocities were deemed as valid since they corresponded to theoretical expectations. Regarding the main goal of the project, it was found that when using inhomogeneous medium, the acoustic streaming would decrease by a factor of 57, in comparison to when homogeneous medium is used. The acoustic streaming is thus mainly influenced by the acoustic radiation force, giving a lateral motion of the polystyrene beads. Ultimately, these results indicate that it will be possible to manipulate and deal with particles as small as bacteria and viruses in acoustophoresis, giving a potential tool, globally speaking, in the fight against aggressive infections in today’s healthcare.},
  author       = {Hajdarovic, Dzenan},
  keyword      = {inhomogeneous medium,density gradients,acoustic streaming,iso-acoustic focusing,acoustophoresis,microchannel,microfluidics,general defocusing particle tracking,astigmatic particle tracking},
  language     = {eng},
  note         = {Student Paper},
  title        = {Suppression of acoustic streaming in liquids of inhomogeneous density and compressibility},
  year         = {2016},
}