Digital microfluidics for biomedical applications

Abstract

Point-of-care (PoC) diagnostic technologies aim to reduce global healthcare disparities by enabling decentralized testing without reliance on advanced laboratory infrastructure. Despite significant progress, many PoC systems remain largely confined to academic research settings, limiting their clinical and societal impact. Digital microfluidics (DMF), a programmable microfluidic approach based on electrowetting-on-dielectric (EWOD), enables the two dimensional controlled manipulation of discrete droplets and offers substantial advantages in flexibility, reconfigurability, and functional integration over conventional continuousflow microfluidic platforms. These characteristics make DMF a promising technological foundation for PoC diagnostics. In the first part of this thesis, the capabilities of a commercially available DMF platform, OpenDrop, are explored for biomedical applications relevant to PoC testing. The platform is employed to perform extracellular vesicle isolation, enzyme-linked immunosorbent assays. In addition, OpenDrop is used to rapidly generate image-based datasets to evaluate the feasibility of applying an in-house, U-Net-based, computer vision framework for droplet detection and classification on DMF devices. Building upon these demonstrations, the second part of this thesis focuses on the design, characterization, and fabrication of a custom DMF platform, designated “Markut.” This development includes computational analysis of the Young–Lippmann equation to guide EWOD optimization, systematic electrowetting experiments conducted in both air and oil to assess dielectric material performance, and the realization of a functional device architecture informed by these results. To support molecular diagnostic applications, a temperature control module is integrated to enable loop-mediated isothermal amplification (LAMP) assays. Furthermore, computer vision–based colorimetric analysis and electrical impedance measurements are incorporated to reliably distinguish between positive and negative LAMP outcomes. Overall, this thesis demonstrates the feasibility and versatility of both commercially available and custom-built DMF platforms for PoC-relevant biomedical applications. The presented results highlight DMF as a robust and scalable technology with strong potential to facilitate the translation of microfluidic diagnostics from laboratory research toward practical, real-world deployment.