CD9-HPLC-IAC Isolation of Serum Extracellular Vesicles for Proteomic Analysis

We developed a column-based CD9 antibody-immobilized HPLC immunoaffinity (CD9-HPLC-IAC) technology for EV isolation from a microliter-scale of serum for downstream proteomic analysis. The CD9-HPLC-IAC method achieved EV isolation from 40 μL of serum in 30 min with a yield of 8.0×109 EVs. Proteomic analysis showed that the common exosomal markers such as CD63, CD81, CD82, Alix, and TSG101 were all identified in EVs. Statistical analysis of EV protein content showed that the top 10 serum proteins in EVs was significantly decreased by using the CD9-HPLC-IAC method compared to the ultracentrifugation (UC) (p=0.001) and size exclusion chromatography (SEC) (p=0.009), and apolipoproteins significantly reduced 4.8-fold compared to the SEC method (p<0.001). The result demonstrated the potential of the CD9-HPLC-IAC method for efficient isolation and proteomic characterization of EVs from a micro-scale volume of serum.