2025 Theses Doctoral

Microfluidic platforms for accessible and sustainable point-of-care molecular diagnostics

Ayers, Abigail

A shift toward decentralized healthcare is transforming medical diagnostics, prioritizing access, affordability, and speed. Traditional testing relies on centralized labs with complex protocols and specialized staff, creating barriers for patients, particularly in remote or resource-limited areas. Point-of-care (POC) technologies offer a practical alternative, enabling rapid, on-site diagnostics that reduce costs and ease pressure on centralized systems. Still, many POC tools struggle with bottlenecks in sample preparation, limited sensitivity, and increasing concerns over environmental and human health impacts.

This thesis addresses two major challenges in POC technology: first, the need for simplified, decentralized sample preparation systems, and second, the environmental burden of single-use plastic diagnostic tools. Aim 1 focuses on the development of an integrated sample preparation platform for infectious disease diagnostics. The system includes a dual-membrane plasma separation module and a user-operated, magnet-driven nucleic acid extraction microfluidic module. This design eliminates the need for complex laboratory equipment by enabling rapid and efficient sample preparation from whole blood using a low-cost, modular platform. Performance testing demonstrates extraction efficiencies and detection limits comparable to conventional lab methods, suggesting strong potential for use in decentralized healthcare environments. This work promotes development of integrated sample preparation systems for addressing roadblocks in POC workflows stemming from challenging samples.

Aim 2 transitions to material innovation, identifying bioplastics as viable alternatives to traditional polymers used in microfluidics. A microfabrication technique, termed STAMP, is introduced to enable precision molding of both bio-based and petrochemical-based materials into microfluidic geometries and applied to several materials. Structural and chemical characterization confirms compatibility of bioplastics with diagnostic bioassays. This aim lays the foundation for a material framework that encourages broader adoption of sustainable materials in diagnostic device development.

Aim 3 validates the diagnostic performance and environmental degradability of the fabricated bioplastic microfluidic devices. A SARS-CoV-2 RT-LAMP assay is implemented to demonstrate real-world diagnostic capability, followed by degradation studies under both home and industrial composting conditions in Rwanda. Results show that bioplastic devices can meet performance standards while enabling more sustainable disposal pathways, unlike conventional plastic-based diagnostics.

Altogether, this work not only advances practical solutions for decentralized diagnostics but also sets a precedent for sustainable design in biomedical device engineering. New generations of diagnostics will demand innovations that move beyond traditional assay development and embrace a systems-level approach that accounts for entire workflows, from sample collection to disposal. Sample preparation and sustainable material integration are no longer peripheral concerns– they are central engineering and ethical challenges that will define the effectiveness, accessibility, and longevity of future diagnostic technologies.