Table 1.

Conventional approaches for exosome isolation

Methods	Principle	Advantages	Disadvantages	References
Ultracentrifugation	Size-based separation	Easy to use, high capacity	Expensive, Time-consuming, exosome damage	[36]
Precipitation	Precipitation of low level solubility components of sample out of solution	Easy to use, cheap	Co-existence with microvesicles, lipoproteins, proteins, and precipitation reagents	[37]
Immunoaffinity	The specific binding between antibody and exosome-specific marker	High yield	Expensive, exosome damage, low yields	[37]
Filtration	Size-based separation	Easy to use, rapid, cheap	Exosome damage, loss of small size exosomes, co-existence with components	[38]
Size exclusion chromatography	Size-based separation, Polymer column filled with nanoporous beads	Maintain the integrity of exosomes, high yield, good reproducibility	Special equipment, co-isolation of albumin and lipoproteins	[39]