Cell Sorting in Pillar Arrays based on Electrokinetics and Morphology
Summary, in English
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.
- Cell Sorting
- Label-Free Separation
- Deterministic Lateral Displacement
- Fysicumarkivet A:2018:Dang Ho
- Jonas Tegenfeldt
- Jason Beech
- Hywel Morgan
- ISBN: 978-91-7753-888-2
- ISBN: 978-91-7753-889-9
23 November 2018
Rydbergsalen, Fysicum, Professorsgatan 1, Lund University, Faculty of Engineering LTH.
- Michael Hughes (Professor)