Isolation and digital counting of extracellular vesicles from blood via membrane-integrated microfluidics

• Published in: Sensors and actuators. B, Chemical Vol. 358; p. 131473
• Main Authors: Chen, Yi-Sin, Chen, Chihchen, Lai, Charles Pin-Kuang, Lee, Gwo-Bin
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.05.2022; Elsevier Science Ltd
• Subjects: Aluminum oxide; Biomarker; Biomarkers; Blood; Body fluids; Extracellular vesicle; Extracellular vesicles; Fluorescence; Membranes; Microfluidics; Nucleic acids; Proteins; Quantification; Vesicles; Biomarker; Membranes; Quantification; Extracellular vesicle; Microfluidics
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2022.131473

Extracellular vesicles (EVs), existing in body fluids, have exhibited a significant potential in clinical diagnostics since many harbor biomarkers specific to certain diseases. Therefore, platforms capable of isolating EVs and quantifying these disease-associated proteins and nucleic acids are under current development. Herein, this study devised a membrane-based EV isolation/counting (mEVic) microfluidic platform that combined two membrane filters to carry out EV isolation from blood, followed by quantification of immuno-stained particles on a single chip. A 0.2-μm polycarbonate membrane was first used for small EV (sEV) isolation via stirring-enhanced filtration, and over 99% of sEV were isolated from only 2 μL of blood. For quantification, aluminum oxide membrane (20 nm)-based immunostaining with in situ fluorescent signal amplification was achieved to where fluorescence-labeled EVs could be individually visualized and counted under a microscope. The limit of detection of CD63 + EVs and PalmGRET EVs spiked in plasma was 105 EVs/mL. Moreover, the membrane-based EV staining assay was able to measure exosomal protein expression on single EVs. This new mEVic platform may therefore serve as a promising tool for isolating and quantifying specific EVs and could be integrated with fingertip-based disease diagnostic applications. •A membrane-based EV isolation/counting (mEVic) microfluidic platform was developed.•Small EV isolation was achieved (~99%) via stirring-enhanced filtration from only 2 μL of blood.•CD63 + EVs were fluorescently labeled, counted and quantified with LOD as low as 105 EVs/mL.