Acoustic manipulation of cells and microbeads in droplet microfluidics
Författare
Summary, in English
The developed microfluidic systems were fabricated in silicon and sealed with glass lids. In the experiments, water droplets containing particles were generated, and an acoustic standing wave-field was created between the channel walls by actuating a piezoelectric transducer attached to the chip. In the first study it was shown that at application of the ultrasound at the first harmonic (1.8 MHz), the encapsulated particles were focused to the centre of the droplets i.e. the pressure node. It was shown that both red blood cells and polystyrene microbeads could be aligned in the centre of the droplets. The usefulness of the technology was proved by combining acoustophoresis with a trident-shaped droplet split to allow for particle enrichment. At application of the ultrasound at the first harmonic close to 90% of the particles were positioned in the centre daughter droplets when approximately 2/3 of the original droplet volume was removed. To better understand the physics of the system, in the second study a theoretical model was developed where the acoustic field inside droplets was investigated. In the third study, switching of encapsulated particles between different microfluidic pathways was shown. At application of the ultrasound at the first harmonic the encapsulated particles were directed into pathway 1 (the centre daughter droplets) while at application of the ultrasound at the second harmonic the encapsulated particles were directed into pathway 2 (the side daughter droplets). In the fourth study, two-dimensional acoustophoresis was used to increase the detectability of particles encapsulated inside droplets by pre-aligning the particles before the droplet generation site. In the fifth and last study, it was demonstrated that acoustophoresis can be used to separate two different particle species originally encapsulated in the same droplet into different daughter droplets based on the acoustic properties of the particles.
This thesis proves that acoustophoresis is a versatile technology that can find various applications in droplet microfluidics. The combination of droplet microfluidics and acoustophoresis opens up for new possibilities for miniaturisation of biological assays on-chip.
Avdelning/ar
Publiceringsår
2018-06-05
Språk
Engelska
Fulltext
- Available as PDF - 34 MB
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Dokumenttyp
Doktorsavhandling
Förlag
Department of Biomedical Engineering, Lund university
Ämne
- Medical Engineering
Nyckelord
- Acoustophoresis
- Droplet microfluidics
- Enrichment
- Lab-on-a-chip
- Particle manipulation
- Ultrasound
Status
Published
Handledare
- Maria Tenje
- Johan Nilsson
- Håkan Jönsson
ISBN/ISSN/Övrigt
- ISBN: 978-91-7753-727-4
- ISBN: 978-91-7753-726-7
Försvarsdatum
24 augusti 2018
Försvarstid
09:15
Försvarsplats
lecture hall E:1406, building E, Ole Römers väg 3, Lund University, Faculty of Engineering LTH, Lund
Opponent
- Adrian Neild (Professor)