Acoustic Standing Wave Manipulation of Particles and Cells in Microfluidic Chips
Author
Summary, in English
The rise of MEMS and µTAS techniques has created a whole new family of microfluidic devices for a wide range of chemical and biomedical analyses to be performed on small Lab-on-a-chip platforms. The operations often include small samples of particle or cell suspensions on which separation, mixing, trapping or sorting is performed. External fields and forces are used for these operations, and this thesis is specifically focused the development of ultrasonic standing wave technology and the use of acoustic force fields to perform bioanalytical unit operations.
The combination of acoustic standing waves and the laminar flow in microfluidics has proven to be well suited for performing particle and cell separation. The fundamental acoustic separator used in this thesis consists of a microfluidic flow channel with a three way flow splitter (trifurcation) in the end of the channel. An acoustic standing wave field is applied to the main flow channel by attaching the transducer underneath the chip. The acoustic standing wave is however obtained perpendicular to the axial propagation of the wave field and the direction of the flow. The half wavelength resonance affects rigid particles or cells driving them into the acoustic pressure node while liquid spheres having other density and compressibility properties may move to the pressure antinode. This enables acoustic separation of different particle types. Blood has proven to be very suitable for acoustic cell manipulation. An application where lipid particles can be removed acoustically from shed blood from open heart surgery is demonstrated. An application for acoustic plasmapheresis is also shown where high quality blood plasma is generated. Different separator designs, device material, and the influence of the separation channel cross-section design are also investigated.
The combination of acoustic standing waves and the laminar flow in microfluidics has proven to be well suited for performing particle and cell separation. The fundamental acoustic separator used in this thesis consists of a microfluidic flow channel with a three way flow splitter (trifurcation) in the end of the channel. An acoustic standing wave field is applied to the main flow channel by attaching the transducer underneath the chip. The acoustic standing wave is however obtained perpendicular to the axial propagation of the wave field and the direction of the flow. The half wavelength resonance affects rigid particles or cells driving them into the acoustic pressure node while liquid spheres having other density and compressibility properties may move to the pressure antinode. This enables acoustic separation of different particle types. Blood has proven to be very suitable for acoustic cell manipulation. An application where lipid particles can be removed acoustically from shed blood from open heart surgery is demonstrated. An application for acoustic plasmapheresis is also shown where high quality blood plasma is generated. Different separator designs, device material, and the influence of the separation channel cross-section design are also investigated.
Department/s
Publishing year
2009
Language
English
Full text
- Available as PDF - 16 MB
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Document type
Dissertation
Publisher
Lund University
Topic
- Medical Engineering
Keywords
- acoustic particle manipulation
- separation
- ultrasound
- cell handling
- particle handling
- lab on a chip
- Microsystem technology
- microfluidics
- standing waves
Status
Published
Supervisor
ISBN/ISSN/Other
- ISBN: 978-91-628-7678-4
Defence date
30 January 2009
Defence time
10:15
Defence place
Room E:1406, E-building, John Erikssons väg 4, Lund University, Faculty of Engineering
Opponent
- Nicole Pamme (Dr)