B-259 Exocas-2 Rapid and Pure Isolation of Exosomes by Anionic Exchange using Magnetic Beads

Abstract Background Extracellular vesicles (EVs) are considered essential biomarkers in liquid biopsies. Despite intensive efforts aimed at employing EVs in a clinical setting, workable approaches are currently limited owing to the fact that EV-isolation technologies are still in a nascent stage. This study introduces a magnetic bead-based ion exchange platform for isolating EVs called ExoCAS-2 (exosome clustering and scattering). Owing to their negative charge, exosomes can easily adhere to magnetic beads coated with a polycationic polymer. Owing to the features of magnetic beads, exosomes can be easily processed via washing and elution steps and isolated with high purity and yield within 40 min. Methods Cationic salt is coated on the surface of magnetic beads with carboxyl group surface residues. Inject the cation coated magnetic bead (ExoCAS) into the plasma solution and incubate in 4°C for 30 minutes. By charge interaction, negative charged EVs are attached to the cationic beads. And then, pH 6 washing buffer and 1M NaCl elution buffer were used for EV isolation. Results The present results confirmed the isolation of exosomes through analyses of size distribution, morphology, surface and internal protein markers, and exosomal RNA. Compared with the commercially available methods, the proposed method showed superior performance in terms of key aspects, including operation time, purity, and recovery rate. Conclusion This highlights the potential of this magnetic bead-based ion exchange platform for isolating exosomes present in blood plasma.