High Throughput Acoustic Focusing for Separation and Interrogation of Biological Particles

摘要

This dissertation develops acoustic standing wave systems to increase the throughput of separation and analysis platforms for biological particles. Across four discrete application spaces, this dissertation demonstrates how the integration of an acoustic standing wave for particle focusing can increase the volumetric and analytical throughput of these systems. Within this process, new instrumentation platforms are developed and fundamental characterization of the acoustic standing wave systems are explored. When applied to the analysis platform of flow cytometry, two new acoustic focusing systems are developed and applied to cytometry instrumentation. First, a high throughput acoustic focusing capillary system is developed for integration into a submersible imaging flow cytometer, the Woods Hole Imaging FlowCytobot. The development of this system explored the fundamental propagation of the wave within the capillary, developed a resonance control strategy to maintain optimal performance and, when integrated into the cytometer, demonstrated the ability to increase the volumetric throughput by an order of magnitude. Second, expanding upon the excitation of a single node system, a highly parallel flow acoustic flow cytometer was developed to increase the volumetric throughputs and analysis rates beyond the traditional limits of a singe stream cytometer. A multinode acoustic standing wave is used to precisely align 16 parallel focused streams of particles for analysis. With appropriate wide field of view optics, this parallelization of the analysis allows for high volumetric (10 mL/min) and analytical (100 k/s) analysis rates, while maintaining optical performance comparable to that of a commercial flow cytometer. This method of parallel interrogation was demonstrated to be relatively simple, cost effective, and compact; it could be impactful across a variety of application spaces that require increased throughput. Similarly, when applied to an electrical impedance sensing platform, increases in throughput and sensitivity are demonstrated with the integration of acoustic focusing. Finally, a fundamental metric for acoustic system performance, the energy efficiency factor (EEF), is demonstrated as a quantitative method for characterizing the performance of an acoustic system at a resonance condition. The EEF can be used as a resonance control strategy and for system characterization, both of which have the potential to improve the viability of low energy ultrasonic harvesting of algae for biofuel production. Across all of these application spaces, the ability of acoustic standing waves to focus particles at high throughputs is characterized and applied to new platforms that benefit from the integration of these focusing systems.