Table I.

Comparison of exosome isolation methods.

Author, year	Method	Principle	Advantages	Disadvantages	(Refs.)
Baranyai et al, 2015; Peterson et al, 2015	UC	Separating the exosomes through differential mass, density and shape	• Available technology	• The high velocity ultracentrifugation process could cause some exosomes rupture that results in some exosomes loss	(37,38)
			• Simple operation
				• Contaminated with albumin and IgG
				• Time consuming (16–20 h)
Li et al, 2017; Zeringer et al, 2015	UF	Depending on exosomal size or molecular weight	• No need of special equipment	• Clogging and vesicle trapping lead to reduce the membranes' lifetime and low isolation efficiency	(35,40)
			• Good portability
Li et al, 2017	Immunom-agnetic beads	Specific exosomal antigens (receptors) can be captured by magnetic beads (ligands)	• High specificity and purity	• High reagent cost	(35)
				• Low yield
			• No damage on the integrity of the exosomes' morphology and structure
Li et al, 2017; Baranyai et al, 2015; Taylor and Shah, 2015	SEC	A porous stationary phase is utilized to sort exosomes out according to the size	• Obtaining high-purity exosomes without significant albumin contamination	• Require dedicated equipment	(35,37,41)
				• Low efficiency
			• Excellent reproducibility and sensitivity
Li et al, 2017; Caradec et al, 2014; Ban et al, 2015	ExoQuick™	By the precipitation approach	• Efficient (around 100%) and reproducible	• Isolation procedure should be under acidic conditions (pH=4)	(35,36,42)
			• Decreasing albumin contamination	• Polymer precipitates protein aggregation
			• Fast (within 30 min)

UC, ultracentrifugation; UF, ultrafiltration; SEC, size exclusion chromatography.