Biomimetic Core–Shell Liposome Nanoparticles Deplete Lipoproteins and Enhance the Purity of Extracellular Vesicles from Human Blood

ABSTRACT Small extracellular vesicles (sEVs) in human serum carry diverse biomarkers and hold great potential for diagnostic and therapeutic applications. However, their isolation is challenging due to the presence of highly abundant serum proteins, particularly lipoproteins that closely resemble the sEVs in size and density. Existing lipoprotein removal methods cannot effectively remove all types of lipoproteins and may lead to potential contamination. Herein, we developed a lipoprotein‐depleting biomimetic core–shell liposome nanoparticle system composed of Fe 3 O 4 @SiO 2 cores coated with liposome bilayers (SL‐NPs). These lipoprotein‐mimicking nanoparticles exhibit efficient binding to lipoproteins that enable the selective removal of lipoproteins by low‐speed centrifugation while preserving sEVs. When applied as a complementary treatment step, this NP depletion strategy further enhances the purity of sEVs isolated from human serum or human plasma using ultracentrifugation or chemical precipitation methods. Nanoparticle tracking analysis, Western blot, ELISA, and proteomics analysis confirm the depletion of multiple classes of lipoproteins and the improvement of sEV purity after this additional nanoparticle depletion step. This strategy offers a simple, rapid, and effective approach to improve downstream biomarker analysis and applications of blood sEVs.