Development and Application of a Novel Acoustic Microfluidic Technology for Single Cell per Well Trapping and High-Resolution Analysis of Cilia Motion in Chlamydomonas Reinhardtii
Date of Award
Doctor of Philosophy (PhD)
Acoustic manipulation of cells and microorganisms is a label-free and contact-free technique with promise for biological and biomedical applications. When exposed to an ultrasonic standing wave field, particles suspended in microfluidic channels will be moved to pressure minima (nodes) or maxima (antinodes) due to the acoustic impedance mismatch between particles and the suspension medium. Cilia motion is fundamental to understanding biological and biomedical problems related to dysfunctional human cilia, including primary ciliary dyskinesia, blindness, and male infertility. However, in vivo and ex vivo mammalian ciliated cell research is laborious and time-consuming due to difficulty in growing, maintaining, and imaging these cells. Therefore, Chlamydomonas reinhardtii (C. reinhardtii), a unicellular alga, has long been used as a genetic and biomedical research model to study cilia. Unfortunately, traditional micropipette-based trapping methods are also laborious and have many limitations including a requirement for physical-contact and being low throughput. So, it is urgent to develop a robust method to trap and study C. reinhardtii cells. In my doctoral research, I developed a novel acoustic technique to trap and analyze C. reinhardtii. First, I completed a thermal analysis of surface acoustic wave (SAW) devices for trapping individual and populations of swimming C. reinhardtii without thermal damage. This study showed that only glass-based SAW can be used to trap swimming C. reinhardtii. Then, I developed a novel acoustic technique to generate two-dimensional standing bulk acoustic waves (BAW) driven by one pair of SAW transducers, which allows trapping and manipulating individual C. reinhardtii with high temporal and spatial resolution. Lastly, cell and cilia dynamics were studied assisted by this novel technique. These studies included probing cilia waveforms, quantitative assessment of C. reinhardtii helical motion, analysis of cilia dynamics variations due to increased fluid viscosity, and the effects of rapid acoustically driven cell translation.
Available for download on Thursday, June 01, 2023