Leveraging Open Microfluidics for Platform Development and Cell-Signaling Studies In Vitro

Abstract

This dissertation discusses the fundamentals, development, validation, and application of open microfluidic technologies as a research tool in biological studies. Open microfluidics is a rapidly evolving and expanding field, characterized by the study of fluid behavior in channels with dimensions < 1 mm and containing at least one interface that is open to the air (i.e., not enclosed). While still a relatively new field, advances in the mathematical theory describing the fluidics in open channels, the fabrication process and resolution, and the creation of application-driven platforms are supporting the use of open microfluidics in biological and chemical studies. The work presented in this dissertation can be broadly separated into two sections: the first, exploring the fundamental mechanics underlying fluid flow in open systems, such as U-shaped channels and rails, to build up general functionalities and toolboxes that include droplet manipulation and hydrogel patterning; and the second, demonstrating the creation and validation of analytical systems to study cell-cell signaling in vitro with customizable cell-targeting beads and a microscale mycobacterial infection model. Through the elucidation of the theory governing fluid behavior in our systems, we can describe the limitations of our open microfluidic systems and incorporate customizable functionalities for various experimental needs, ultimately improving the transferability of the systems to collaborators and other researchers (Chapters 2 and 3). We couple this fundamental design approach with applications in cell-cell signaling, a vital biological phenomenon that plays important roles in immune response, homeostasis, organ development and function, and tissue repair. However, the microenvironments where these complex intercellular signaling processes occur are difficult to study and prevent researchers from deciphering the role of important cellular communication, illustrating a need for new technologies and approaches to better model and probe these systems (Chapter 4). To partially address this need, we present the development and validation of two novel approaches to study intercellular signaling that can be easily adapted and customized for use in different settings (Chapter 5 and 6). Ultimately, the techniques and technologies described here represent foundational analytical and modeling approaches and warrant further development to increase their potential impact.