TABLE 1.

Comparison of strategies for exosome isolation and enrichment.

Strategy	Mechanism	Advantages	Limitations	Reference
Differential ultracentrifugation	density	a standard protocol, large sample volume	low yields and specificity, long time (more than 4 h), low purity, needs ultracentrifuge	Shao et al. (2018); Théry et al. (2006)
Gradient ultracentrifugation	density	a standard protocol, high purity	low yields, long time (more than 4 h), more complex operation steps, needs ultracentrifuge	Shao et al. (2018); Paolini et al. (2016)
Size-exclusion chromatography	size	fast and easy preparation, both small and large sample volume	low specificity, relatively high device cost	Zheng et al. (2020); Guo et al. (2021)
Ultrafiltration	size	fast and easy preparation, both small and large sample volume	low specificity, possible loss due to clogging	Liu et al. (2017); Chen et al. (2021)
Polymer precipitation	solubility	easy preparation, high yields, large sample volume	low specificity, long processing time (more than 12 h)	Yang et al. (2020)
Affinity capture	molecular recognition	high purity, suitable for small volume diagnosis	requires high-cost antibody, needs to select exosome markers	Chang et al. (2020); Yang et al. (2020)
Microfluidic technique	multiple principles, including affinity or size	portable and integrable, cost-efficient, fast preparation, high purity	low sample capacity, complex fabrication	Lin et al. (2020)