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| Extraction techniques of exosomes | The principle of extraction | Advantage | Disadvantage | Clinical applicability | References |
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| Differential centrifugal (DC) | Due to the differences in particle size, shape, and density, the particle settlement coefficient in the solvent is also different. By increasing the centrifugal speed by grading, different particles are settled from the mixed liquid to the bottom of the tube in batches to achieve separation | It can satisfy the extraction of a large sample size
Low pollution risk
Saving reagent cost | The operation is difficult, and the cost is high
Long extraction time
Exos are damaged during centrifugation
It has an impact on the therapeutic effect | No | [57–62] |
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| Density gradient centrifugation (DGC) | Using gradient media to remove vesicle particles | Good separation effect
Having a higher concentration
Maintaining certain particle activity
Preventing the effect of convective mixing on purity | It takes a long time
The operation is difficult | No | [67] |
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| Ultrafiltration (UF) | Exosomes and other macromolecules are trapped in the filtration membrane by pressurizing the solvent and small molecules through the filtration membrane | Easy to operate
High enrichment rate
Low cost | Filter membrane blockage
Low purity
There is contamination
Difficult to recover during elution | No | [68, 69] |
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| Size exclusion chromatography (SEC) | According to the size difference between exos and other particles, the protein was purified by similar chromatography | It can ensure the activity and integrity of exos
Higher yield
Short time | Special instruments are needed
There is a minimum exos load limit | Yes | [70, 71] |
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| Immune capture (IC) | Isolation is performed by binding specific antibodies to antigen receptors on the surface of exos | Higher purity | Cost prohibitive | Suitable for specific diseases, but not large-scale preparation | [72] |
| Suitable for subtype isolation | May affect immune recognition |
| The effect on the structure of the exos membrane is small | Cannot be prepared in large quantities |
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| Precip | The solubility and dispersibility of exos were changed by hydrophobic polymer, and exos were extracted by sedimentation under low centrifugal force | Easy to operate | Mixed with some pollutants (protein) | Yes | [70] |
| Low requirements for equipment |
| Suitable for high-dose treatment |
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| Microfluidic technology | The isolation and extraction of exos were dependent on the immunoaffinity, size, and density of EXOS | High purity and recovery
Short time
Good biocompatibility | Low flux
High requirements for equipment | Yes | [73–76] |
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| Two-phase isolation | Incubation in a polyethylene glycol-dextran mixture | Low cost | Repeated replacement of the polyethylene glycol phase is required | Yes | [77] |
| Simple process |
| No deformation of EVs |
| High purity |
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| Binding of heat shock proteins | Isolation of heat shock protein-modified EVs by polymerization using the heat shock protein (HSP)-binding peptide Vn96 | High EVs integrity | Costly | No | [78, 79] |
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