PASSIVE AND ACTIVE MANIPULATION OF MICRO-PARTICLES WITH ACOUSTIC WAVES
Open Access
- Author:
- Ren, Liqiang
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- April 15, 2019
- Committee Members:
- Thomas E. Mallouk, Dissertation Advisor/Co-Advisor
Thomas E. Mallouk, Committee Chair/Co-Chair
Corina Drapaca, Committee Member
Bruce J. Gluckman, Committee Member
Siyang Zheng, Outside Member - Keywords:
- microparticle manipulation
acoustofluidics
microfluidics
micromotors/microswimmers
surface acoustic wave
autonomous motion - Abstract:
- The precise manipulation of micro/nano particles plays an essential role in many fields such as nanotechnology, biomedicine and chemical engineering, both for fundamental scientific research and for practical applications. Among the many techniques that have been developed for this purpose, acoustically-based methods demonstrate a combination of advantages that competing techniques lack: contactless, label-free and non-invasive manipulation, easy fabrication and compact devices, high biocompatibility, compatibility with microfluidics for small volume samples, and high resistance to interference by other energy sources such as optical or magnetic fields. Based on the nature of the response of micro/nano particles to an acoustic field, acoustic manipulation techniques can be classified as either passive or active. In the case of passive manipulation, the acoustic radiation force that traps particles at pressure nodes (or anti-nodes) in a standing acoustic wave field is the major physical effect that is utilized. Since the direction and magnitude of the acoustic force depend on the properties of the particles, many applications including cell separation and sorting can be realized by this method. In contrast to passive manipulation, active manipulation uses acoustic waves to power the autonomous motion of microparticles, which means that the microparticles can move independently of each other and of the propagating direction of the acoustic waves. The microparticles that are actively manipulated are also called micromotors or microswimmers. Micromotors significantly enrich the functions of acoustic manipulation by demonstrating emergent microorganism-like individual or collective behaviour. They have brought new capabilities to several research fields, and applications such as biosensing, drug delivery, particle assembly, and microsurgery are currently being developed. This dissertation focuses on understanding and developing novel techniques for microparticle manipulation by applying both passive and active approaches. Specifically, these techniques include: (1) A high-throughput standing surface acoustic wave (SSAW)-based cell sorting unit; (2) an on-chip flow cytometer for analysis of induced sputum; (3) a standing surface acoustic wave (SSAW)-based fluorescence-activated cell sorter; (4) a study of rheotactic bimetallic micromotors driven by chemical-acoustic hybrid power; and (5) a class of 3D steerable, acoustically powered microswimmers for single-particle manipulation. We expect that these techniques will begin to address some of the important remaining fundamental challenges in the field of microparticle manipulation and will significantly benefit related applications such as single cell study and point-of-care diagnosis.