Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Jonas Tegenfeldt

Professor, Coordinator Nanobiology & Neuronanoscience

Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Cell Sorting in Pillar Arrays based on Electrokinetics and Morphology

Author

  • Bao Dang Ho

Summary, in English

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.

Department/s

  • Solid State Physics
  • NanoLund

Publishing year

2018-10-18

Language

English

Document type

Dissertation

Publisher

Department of Physics, Lund University

Topic

  • Biophysics

Keywords

  • Cell Sorting
  • Label-Free Separation
  • Deterministic Lateral Displacement
  • Electrokinetics
  • Fysicumarkivet A:2018:Dang Ho

Status

Published

Supervisor

  • Jonas Tegenfeldt
  • Jason Beech
  • Hywel Morgan

ISBN/ISSN/Other

  • ISBN: 978-91-7753-888-2
  • ISBN: 978-91-7753-889-9

Defence date

23 November 2018

Defence time

09:15

Defence place

Rydbergsalen, Fysicum, Professorsgatan 1, Lund University, Faculty of Engineering LTH.

Opponent

  • Michael Hughes (Professor)