Isolation and Characterization of Cell- and Size-Specific Extracellular Vesicles by Nanoscale High Resolution Flow Cytometry

Cells release extracellular vesicles (EVs) into the circulation that range in size from exosomes to larger microvesicles and apoptotic fragments. EVs arise from the plasma membrane and contain cell-specific surface antigens (e.g. placental alkaline phosphatase [PLAP] in pregnant women) and various tetraspanins (e.g. CD9). Cell-specific surface antigens provide a means to isolate cell-specific EVs by affinity capture, or to test for antigen enrichment in EV preparations like ultracentrifugation and density gradient fractions. Currently, EV quantitation, sizing, and isolation are hindered by the lack of an approach that can provide both cell-and size-specificity.