TABLE 2.
Different aspects of exosomes.
| Feature | Exosome | Apoptotic body | MV |
| Size | Homologous 30–100 nm | Heterogeneous 1–5 μm | Heterogeneous 100–1000 nm |
| Markers | Membrane impermeable (PI negative) CD63, TSG101, Alix, flottilin | Membrane permeable (PI positive) Annexin V, DNA, histones | Membrane impermeable (PI negative) integrin, selectin, flotillin-2 |
| Density | 1.13–1.19 g/mL | 1.16–1.28 g/mL | 1.25–1.30 g/mL |
| Contents | Protein, lipid, different RNA species, and DNA | Cytosolic content (protein, RNAs, fragmented DNA) and cellular organelles | Protein, lipid, different RNA species, and DNA |
| Determinant of controlled contents | The cellular origin and physiological state of the cell | The cellular origin and stimuli | No direct correlation |
| Lipids | A major sorting of lipidic molecules from the parental cells (include BMP) | Characterized by phosphatidylserine externalization | The lipid contents are primarily derived from plasma membrane, and resemble the parental cells (without BMP) |
| Origin | Multivesicular bodies fusion with plasmatic membrane | Cellular debris, plasma membrane blebbing during cell apoptosis | Direct outward budding or blebbing from the plasma membrane |
| Mechanism of release | Constitutive or inducible, depending on the cell type of origin | Rho-associated kinase I and myosin ATPase activity | Relocation of phospholipids to the outer membrane, cytoskeleton rearrangements, generation of membrane curvature, and vesicle release |
| Detection methods | Electron microscopy, Western blot for exosome enriched markers | Flow cytometry, electron microscopy, | Flow cytometry, electron microscopy |
| Isolation methods | Ultracentrifugation (100,000–200,000 × g) filtration, density gradient Immunoprecipitation, Immune affinity capture and ExoQuick precipitation methods | Ultracentrifugation (10,000–20,000 × g) | No standardized methods |
| Modification methods | Incubation, Sonication, Extrusion, Freeze thaw, Electroporation, Chemical transfection, Genetic engineering | ||
| Size determination and quantification | Dynamic light scattering Nanoparticle tracking analysis Surface plasmon resonance |
MV, microvesicle; BMP, bone morphogenetic protein; PI, propidium iodide. Adopted from Zhang et al. (2019) distributed under the Creative Commons Attribution 4.0 International License.