Integrated Microfluidic Device for Accurate Extracellular Vesicle Quantification and Protein Markers Analysis Directly from Human Whole Blood

Extracellular vesicles (EVs) have the potential to be utilized as disease-specific biomarkers. Although strategies for on-chip isolation and detection of EVs have recently been developed, they need preprocessing of clinical samples and are not accurate enough for disease diagnosis just judging by EVs concentration. Here, we designed an integrated microfluidic device named a plasma separation and EV detection (PS-ED) chip for plasma separation, quantification, and high-throughput protein analysis of EVs directly from clinical whole blood samples. The device included two modules (PS and ED module): the PS module was a six-loop microchannel for rapid separation of plasma from clinical whole blood samples under inertial force; the amount of EVs in the separated plasma kept the same value as in the initial blood samples. The module reduced the mechanical damage to the blood cells and thus reduced the interference of debris or cellular contents from damaged cells during EVs detection; the ED module contained four S-channels for quantification and high-throughput protein analysis of EVs; a wide detection range from 2.5 × 102 to 2.5 × 108 particles/μL with a detection limit of 95 particles/μL was obtained. Through simultanously monitoring three proteins (CD81, CD24, and EpCAM) of EVs, the cancer type can be accurately confirmed. Furthermore, clinical blood sample analysis verified that the proposed device could be used for accurate diagnosis and therapy monitoring of ovarian cancer.