EV-Lev: extracellular vesicle isolation from human plasma using microfluidic magnetic levitation device

Abstract

Biological nanomaterials have unique magnetic and density characteristics that can be employed to isolate them into subpopulations. Extracellular nanovesicles (EVs) are crucial for cellular communication; however, their isolation poses significant challenges due to their diverse sizes and compositions. We present EV-Lev, a microfluidic magnetic levitation technique for high-throughput, selective isolation of small EVs (<200 nm) from human plasma. EV-Lev overcomes the challenges posed by the subtle buoyancy characteristics of EVs, whose small size and varied densities complicate traditional magnetic levitation techniques. It employs antibody-coated polymer beads of varying densities, integrating immuno-affinity and microfluidics to isolate EVs from sub-milliliter plasma volumes efficiently. It facilitates rapid, simultaneous sorting of EV subpopulations based on surface markers, such as CD9, CD63, and CD81, achieving high yield and purity. Subsequent size and morphology analyses confirmed that the isolated EVs maintain their structural integrity. EV-Lev could help uncover the cargo and function of EV subpopulations associated with multiple diseases including cancer, infectious diseases and help to discover potential biomarkers in small volume samples, while offering a portable, cost-effective, and straightforward assay scheme.