Isolation and Characterization of Exosomes

Exosomes were isolated by size exclusion chromatography (SEC) as previously described.^{26 (link)} Exosomes were collected in fraction #4 (1 mL). For some experiments, #4 mini-SEC fractions were concentrated to 1 µg/µL using 100 000 MWCO Vivaspin 500 Centrifugal Concentrators (Sartorius Corp, #7321011) at 5000 × g for 5–10 min. Protein contents were measured using the BCA protein assay kit (Thermo Scientific, REF 23225). Transmission electron microscopy (TEM), tunable resistive pulse sensing measurements, and western blots were used to determine morphology, size, particle concentration, and protein cargo of exosomes as previously described by us.^{27 (link)}