Built to Share: Modular Design Tools for Accessible Microfluidics and Decentralized Diagnostics

Abstract

Modern microfluidics offers transformative potential for global health, but realizing that promise requires tools that are not only capable, but also accessible, adaptable, and designed for sharing. This dissertation advances a modular design philosophy for decentralized diagnostics and fluidic autonomy, focusing on approaches that eliminate reliance on expensive infrastructure.Chapter 1 addresses a pressing global health challenge: therapeutic drug monitoring (TDM) for HIV treatment and prevention. I introduce RESTRICT and REACT, enzymatic assays that quantify pharmacologic activity of antiretroviral drugs, providing clinically validated, equipment-light alternatives to LC-MS/MS. These assays enable long-term adherence monitoring in low-resource and point-of-care settings and motivate the pursuit of self-driven microfluidic systems capable of automation without external pumps or power. Chapter 2 develops and formalizes the microfluidic chain reaction (MCR) as a programmable capillaric architecture. By framing MCRs in a circuit-based analytical model and producing open-source design tools, I bridge theoretical potential and practical deployment, enabling fluidic workflows to be encoded directly into chip geometry. This framework defines design rules, failure modes, and implementation strategies for autonomous fluid handling. Chapter 3 evaluates fabrication strategies for capillaric systems outside of cleanroom environments, focusing on cost, resolution, and ease of implementation. I assess low-cost LCD 3D printers alongside conventional DLP systems, documenting achievable feature dimensions, common print failures, and post-processing techniques. Practical guidance is provided for assembly, integration of capillary pumps, interfacing components, and adapting designs for accessible manufacturing. These methods lower the barrier for fabricating functional, programmable microfluidic circuits in resource-limited settings. Chapter 4 extends the capillarics toolkit by adapting two advanced cleanroom- fabricated geometries, phaseguides for sequential fluid routing and SCMs for reagent resuspension, into printable forms compatible with low-cost LCD 3D printers. I characterize their operation, identify design constraints imposed by printer resolution, and validate performance in fluid routing and pulse-shaped reagent delivery. A sharable STL library, failure mode atlas, and Python-based analysis scripts accompany these designs, enabling reproducibility and adaptation by other researchers. Together, these contributions establish a shareable toolbox of assays, geometries, fabrication methods, and analytical frameworks for building autonomous, modular microfluidic devices. The work shifts high-performance microfluidics from cleanroom exclusivity toward open, distributed manufacturing, broadening who can design, build, and deploy diagnostic systems in both research and global health contexts.