Isolation of small extracellular vesicles from a drop of plasma via EXODUS and their fingerprint proteomics profiling by MALDI-TOF MS

Small extracellular vesicles (sEVs) in blood have emerged as the most promising biomarkers for clinical diagnostics and prognostics. However, isolation and identification of intact sEVs from blood are the major obstacles for basic research and clinical translations. Here, we report rapid isolation and sensitive detection of plasma sEVs by an integrative platform of sEV detection via the ultrafast-isolation system (EXODUS) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We can achieve label-free isolation of sEVs with relatively high recovery and purity by the EXODUS purification method from 20 μL of plasma, which was compared with polyethylene glycol-based precipitation and ultracentrifugation methods. We have profiled the fingerprints of the intact sEVs isolated from the different volumes of plasma using MALDI-TOF MS within 1 h. Further, we have evaluated the reproducibility and identified the metabolomic biomarkers of plasma sEVs via LC-ESI-MS/MS. We believe the combination of rapid EXODUS isolation and MALDI-TOF MS detection may serve as a clinical translation method for fast and high-throughput biomarker detection and screening.