Sorting Particles by Deterministic Lateral Displacement : Effects of Shape and Size from Single Particles to Clusters
(2026)- Abstract
- This thesis investigates particle sorting in deterministic lateral displacement (DLD) microfluidic devices, with a focus on how particle size and shape influence sorting behavior. A broad range of synthetic and biological particles were studied, including polystyrene particles, fabricated silicon-based structures, and bacterial samples with diverse physical properties.
While DLD has traditionally been applied to particles with well-defined and discrete size and shape, this work addresses complex samples with continuous size and shape distributions, which remain challenging for conventional DLD-based separation. Group A Streptococcus (GAS) bacteria were used as a model biological sample due to their tendency to form clusters of... (More) - This thesis investigates particle sorting in deterministic lateral displacement (DLD) microfluidic devices, with a focus on how particle size and shape influence sorting behavior. A broad range of synthetic and biological particles were studied, including polystyrene particles, fabricated silicon-based structures, and bacterial samples with diverse physical properties.
While DLD has traditionally been applied to particles with well-defined and discrete size and shape, this work addresses complex samples with continuous size and shape distributions, which remain challenging for conventional DLD-based separation. Group A Streptococcus (GAS) bacteria were used as a model biological sample due to their tendency to form clusters of varying size and shape, spanning a wide size range from approximately 0.8 to 100µm. By employing a DLD array with high periodicity, effective size-based separation of these bacterial clusters was achieved. This enabled subsequent biological investigations, in which sorted clusters of different sizes were exposed to human immune cells, revealing that bacterial clustering can influences pathogenic activity.
The role of particle shape in DLD sorting was further examined using samples with well-defined geometries. Non-spherical polystyrene particles were first studied to quantify how shape affects particle–post interactions and sorting outcomes. This analysis was extended to biological samples, including small bacterial chains and clusters, demonstrating that particle shape induces distinct rotational dynamics during transport in laminar flow and interaction with DLD posts. Particle symmetry was found to play a key factor in determining sorting behavior.
Motivated by these findings, a systematic investigation of shape-dependent sorting was conducted using custom-fabricated particles with continuously varying shapes. Together, these results provide a basis for the tailored design of DLD devices capable of separating bioparticles with complex morphologies and physical properties, such as cell clusters and diverse bacterial forms. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/5e6114e4-6e39-493f-bfbb-418f304424c2
- author
- Akbari, Elham LU
- supervisor
-
- Jonas Tegenfeldt LU
- Jason Beech LU
- Pontus Nordenfelt LU
- opponent
-
- Prof. Russom, Aman, KTH Royal Institute of Technology, Sweden.
- organization
- publishing date
- 2026-03-03
- type
- Thesis
- publication status
- published
- subject
- pages
- 186 pages
- publisher
- Department of Physics, Lund University
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund. The dissertation will be live streamed, but part of the premises is to be excluded from the live stream.
- defense date
- 2026-04-10 09:15:00
- ISBN
- 123456789
- 123456789
- language
- English
- LU publication?
- yes
- id
- 5e6114e4-6e39-493f-bfbb-418f304424c2
- date added to LUP
- 2026-03-09 13:28:55
- date last changed
- 2026-03-13 09:39:30
@phdthesis{5e6114e4-6e39-493f-bfbb-418f304424c2,
abstract = {{This thesis investigates particle sorting in deterministic lateral displacement (DLD) microfluidic devices, with a focus on how particle size and shape influence sorting behavior. A broad range of synthetic and biological particles were studied, including polystyrene particles, fabricated silicon-based structures, and bacterial samples with diverse physical properties.<br/><br/>While DLD has traditionally been applied to particles with well-defined and discrete size and shape, this work addresses complex samples with continuous size and shape distributions, which remain challenging for conventional DLD-based separation. Group A Streptococcus (GAS) bacteria were used as a model biological sample due to their tendency to form clusters of varying size and shape, spanning a wide size range from approximately 0.8 to 100µm. By employing a DLD array with high periodicity, effective size-based separation of these bacterial clusters was achieved. This enabled subsequent biological investigations, in which sorted clusters of different sizes were exposed to human immune cells, revealing that bacterial clustering can influences pathogenic activity.<br/><br/>The role of particle shape in DLD sorting was further examined using samples with well-defined geometries. Non-spherical polystyrene particles were first studied to quantify how shape affects particle–post interactions and sorting outcomes. This analysis was extended to biological samples, including small bacterial chains and clusters, demonstrating that particle shape induces distinct rotational dynamics during transport in laminar flow and interaction with DLD posts. Particle symmetry was found to play a key factor in determining sorting behavior.<br/><br/>Motivated by these findings, a systematic investigation of shape-dependent sorting was conducted using custom-fabricated particles with continuously varying shapes. Together, these results provide a basis for the tailored design of DLD devices capable of separating bioparticles with complex morphologies and physical properties, such as cell clusters and diverse bacterial forms.}},
author = {{Akbari, Elham}},
isbn = {{123456789}},
language = {{eng}},
month = {{03}},
publisher = {{Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Sorting Particles by Deterministic Lateral Displacement : Effects of Shape and Size from Single Particles to Clusters}},
year = {{2026}},
}