The Versatility and Applicability of Droplet Microfluidics

Abstract

New drugs are currently being developed to cure once incurable diseases through medications that involve gene and antibody therapies. These therapies won't work without targeted delivery systems. We need to identify the lock and key mechanism for such systems. An effective model for developing a drug delivery system must take into account the requirements of size, stability, and targeting ability. My thesis presents a model system using droplet microfluidics to produce a tuneable capsule that can be used for drug delivery systems. I use emulsion science and with microfluidics to produce multilayered capsules that are used as a model drug delivery system. In the first chapter of my thesis, I describe the fundamentals of emulsions--how they are formed and stabilized. In chapter 2, I write about a new rapidly prototyped microfluidic device that I developed throughout my thesis. In order to produce the capsules for drug delivery systems using emulsion templates it was essential that I use organic solvents as the oil phase. However, the most commonly used microfluidics device which uses a soft elastomer, PDMS, as its main material, swells immediately upon contact with any organic solvent. My solution replaces PDMS with an organic solvent compatible material whilst maintaining the simplicity of rapid prototyping associated with PDMS. Chapter 3 addresses the challenge of trying to make double emulsion templates that produce membrane enclosed vesicles. Existing formulations allowed for the production of double emulsions, but most of the double emulsions did not survive the transition phase from a template to a vesicle. We report a formulation that generated a high yield of vesicles from double emulsion templates. We found that the formula combined with a microfluidics technique produced nearly 100% yield of vesicles. Chapter 4 discusses using droplet microfluidics as a tool for high throughput screening assays. As part as of an industrial collaboration, we partnered with BASF to develop an acoustic picoinjector. This technology is used to inject preexisting droplets with additional material. We designed a new acoustic picoinjector that can inject 1000 droplets per second with a uniform volume of injection material. This chapter also describes the physics behind Traveling Surface Acoustic Waves (TSAW) and how it can be integrated into a microfluidics device to inject fluids into droplets.