TABLE 1.

Summary of EV isolation methods.

Isolation method	Isolation mechanism	Advantages	Disadvantages	References
Ultracentrifugation	Density	Gold standard method, widely used	EVs yields are low	Thery et al. (2006), Lobb et al. (2015), Nigro et al. (2021)
			Long process
Density gradient centrifugation	Density	High purity	Cumbersome operation; time-consuming	Ashley et al. (2018)
Size exclusion chromatography	Particle size	Used for large-scale samples	Each consumable can only handle samples from the same source, which is too costly if used for the separation of different clinical samples	(Boing et al. (2014), Guo et al. (2021)
Ultrafiltration	Particle size	The separation steps are simple and fast	Cannot remove similar-sized protein particles	(Haraszti et al. (2018), Li et al. (2019), Chen et al. (2021)
Co-precipitation	Surface charge	Simple and fast separation steps	Contamination of organelle-related proteins, not conducive to downstream detection	Rider et al. (2016), Ludwig et al. (2018)
Immunoaffinity enrichment	Antigen–antibody	Obtain EVs expressing specific proteins	Bind to free proteins and affects the capture efficiency of EVs; low recovery	Choi et al. (2021)
Field flow fractionation	Molecular weight	Wide range of separations	Special equipment; low-throughput	Zhang and Lyden, (2019)
Acoustic-based isolation method	Sound wave	The separation steps are simple and fast	Not suitable for complex samples	Lee et al. (2015b), Tayebi et al. (2021)
Metallic oxide-based isolation method	electrostatic interaction, physically absorption and biorecognition	Fast and simple; small sample volume; Low cost	Not conducive to downstream detection	Gao et al. (2019a), Dao et al. (2022)
Absorbent polymer-based method	Particle size	High-efficiency, No special equipment	Low purity; not suitable for complex samples	Yang et al. (2021)