The EV identity is dependent on its corona

Extracellular vesicles (EVs) function as communicators between cells in the extra- cellular space. However, the extravesicular space is rich in biomolecules, which form a layer on surfaces. In this work, we investigated how the identity of the naive EVs changes with the deposition of a albumin layer, known commonly as a corona. The heterogeneity of the naive EVs was reflected also in their corona. At low concentrations of albumin, the corona may change the apparent zeta potential of the EVs. At cell culture concentrations of albumin (≈ 60μM), surface markers may become unavailabile for antibodies to bind and the size increases. Finally, at blood serum concentrations of albumin (≈ 600μM) the albumin corona blocks the majority (> 50 %) of the surface markers and alters the size and zeta potential of the naive EVs. The work emphasises the dependence of the EV identity on the surrounding molecules, which can explain differences in biological function.