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Cell Sorting in Pillar Arrays based on Electrokinetics and Morphology

Ho, Bao Dang LU (2018)
Abstract
Deterministic Lateral Displacement (DLD) is a method capable of sorting cells based on size where mechanical
interactions between a sufficiently large particle and obstacles in a microfludic pillar array force the particle to
follow a different trajectory than their smaller counterparts, resulting in continuous lateral separation. To extend
the capability of DLD, electrical interaction between particles and pillars can be employed to complement the
mechanical interaction, making electrical/dielectric properties additional parameters for sorting. Another idea is
to exploit the morphologies of cells and as a concequence, their dynamical properties, to sort them in DLD. The
development of DLD cell sorting methods based... (More)
Deterministic Lateral Displacement (DLD) is a method capable of sorting cells based on size where mechanical
interactions between a sufficiently large particle and obstacles in a microfludic pillar array force the particle to
follow a different trajectory than their smaller counterparts, resulting in continuous lateral separation. To extend
the capability of DLD, electrical interaction between particles and pillars can be employed to complement the
mechanical interaction, making electrical/dielectric properties additional parameters for sorting. Another idea is
to exploit the morphologies of cells and as a concequence, their dynamical properties, to sort them in DLD. The
development of DLD cell sorting methods based on those two ideas has brought forth five papers appended to this
thesis: paper I, III, and V (combination of electrokinetics and DLD), and paper II and IV (exploiting morphology
in sorting by DLD).
In the first topic, differences in electric properties or dielectric properties of particles and cells are employed to
extend the capability of DLD. In Paper I, an AC electric field was applied across DLD devices having insulating
pillars to sort similar-sized polystyrene particles having different surface charge, viable from non-viable yeast cells,
and viable from non-viable E. coli bacteria. In Paper III, the same method was utilised on open channel DLD
devices, showing unaltered effectiveness but offering the ability to flexibly change the distance between the electrodes.
Also in the topic of combining electrokinetics and DLD, Paper V introduced a new type of DLD device
where the electrodes were defined locally on every pillar, making it easier to generate a high electric field strength.
Besides electrical properties, morphology is another useful accompaniment to DLD. In Paper II, pathogenic
Streptococcus pneumoniae bacteria were fractionated in DLD devices according to the difference in their morphology,
viz. their chain length. It was also demonstrated, in paper IV, that an AC field can be used to rotate
non-spherical red blood cells and in turn, change their trajectory in a DLD device. This implies an opportunity to
sort red blood cells from cells having different morphology, either spherical cells or parasites like trypanosomes. (Less)
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author
supervisor
opponent
  • Professor Hughes, Michael, University of Surrey, Guildford, United Kingdom
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Cell Sorting, Label-Free Separation, Deterministic Lateral Displacement, Electrokinetics, Fysicumarkivet A:2018:Dang Ho
pages
199 pages
publisher
Department of Physics, Lund University
defense location
Rydbergsalen, Fysicum, Professorsgatan 1, Lund University, Faculty of Engineering LTH.
defense date
2018-11-23 09:15
ISBN
978-91-7753-888-2
978-91-7753-889-9
language
English
LU publication?
yes
id
fc3d4f12-6bec-4fc4-b778-c84747b66259
date added to LUP
2018-10-25 22:31:31
date last changed
2019-07-05 17:00:36
@phdthesis{fc3d4f12-6bec-4fc4-b778-c84747b66259,
  abstract     = {Deterministic Lateral Displacement (DLD) is a method capable of sorting cells based on size where mechanical<br/>interactions between a sufficiently large particle and obstacles in a microfludic pillar array force the particle to<br/>follow a different trajectory than their smaller counterparts, resulting in continuous lateral separation. To extend<br/>the capability of DLD, electrical interaction between particles and pillars can be employed to complement the<br/>mechanical interaction, making electrical/dielectric properties additional parameters for sorting. Another idea is<br/>to exploit the morphologies of cells and as a concequence, their dynamical properties, to sort them in DLD. The<br/>development of DLD cell sorting methods based on those two ideas has brought forth five papers appended to this<br/>thesis: paper I, III, and V (combination of electrokinetics and DLD), and paper II and IV (exploiting morphology<br/>in sorting by DLD).<br/>In the first topic, differences in electric properties or dielectric properties of particles and cells are employed to<br/>extend the capability of DLD. In Paper I, an AC electric field was applied across DLD devices having insulating<br/>pillars to sort similar-sized polystyrene particles having different surface charge, viable from non-viable yeast cells,<br/>and viable from non-viable E. coli bacteria. In Paper III, the same method was utilised on open channel DLD<br/>devices, showing unaltered effectiveness but offering the ability to flexibly change the distance between the electrodes.<br/>Also in the topic of combining electrokinetics and DLD, Paper V introduced a new type of DLD device<br/>where the electrodes were defined locally on every pillar, making it easier to generate a high electric field strength.<br/>Besides electrical properties, morphology is another useful accompaniment to DLD. In Paper II, pathogenic<br/>Streptococcus pneumoniae bacteria were fractionated in DLD devices according to the difference in their morphology,<br/>viz. their chain length. It was also demonstrated, in paper IV, that an AC field can be used to rotate<br/>non-spherical red blood cells and in turn, change their trajectory in a DLD device. This implies an opportunity to<br/>sort red blood cells from cells having different morphology, either spherical cells or parasites like trypanosomes.},
  author       = {Ho, Bao Dang},
  isbn         = {978-91-7753-888-2},
  keyword      = {Cell Sorting,Label-Free Separation,Deterministic Lateral Displacement,Electrokinetics,Fysicumarkivet A:2018:Dang Ho},
  language     = {eng},
  month        = {10},
  pages        = {199},
  publisher    = {Department of Physics, Lund University},
  school       = {Lund University},
  title        = {Cell Sorting in Pillar Arrays based on Electrokinetics and Morphology},
  year         = {2018},
}