An Integrated Digital Microfluidic Device for the Extraction and Detection of Extracellular Vesicle-Based Molecules.

Extracellular vesicles (EV) are phospholipid-encapsulated nanoparticles secreted by cells into their surrounding environment. EVs can transfer a variety of biomolecules that mediate intercellular communication and play a key role in physiological and pathological processes. Therefore, EVs are emerging as new biomarkers for diseases, therapeutic targets, and drug delivery vehicles. The isolation and detection of EVs requires time-consuming and labor-intensive processes, first to extract EVs from biological and physiological fluids and then to detect EV-associated molecules with high sensitivity. The methodologies and instruments commonly used for EV analysis are not widely accessible outside of dedicated research laboratories, creating practical barriers for the study of EV-associated molecules in biology research and clinical applications. To bridge this gap, we developed a proof-of-concept digital microfluidic device that can automatedly extract EVs from 20 µL of culture and human plasma samples within 25 min and detect EV-bound proteins (e.g PD-L1) on-chip using an electrochemical sensor. This work serves as a framework for the development of streamlined EV analysis in both research and diagnostics.