Table 1.

Summary of isolation and purification method of EVs.

Isolation method	Principle of isolation	Characteristic	Grade of isolation efficiency
Ultracentrifugation-based isolation techniques	Density, size, and shape based sequential separations of particulate constituents and solutes	Large sample capacity and yielding of large amounts of exosomes, but high equipment cost, cumbersome, long run time and high speed centrifugation may damage exosomes	Low recovery and high specificity
Size-based isolation techniques	Size difference between exosomes and other particulate constituents	Low equipment cost and fast but shear stress induced deterioration and exosomes loss due to attaching to the filter membranes	Intermediate recovery and intermediate specificity
Immunoaffinity capture- based techniques	Specific interaction between membrane-bound antigens (receptors) of exosomes and immobilized antibodies (ligands)	Suitable for the isolation of specific exosomes with high specificity, but high reagent cost, exosome tags need to be established, low sample capacity and low yields	Low recovery and high specificity
Precipitation	Altering the solubility or dispersibility or exosomes by the use of water-excluding polymers	Easy to use, no need for special equipment, high sample capacity, but low specificity and co-precipitation of other non-exosomal contaminants like proteins and polymeric materials	High recovery and low specificity
Microfluidics-based isolation techniques	A variety of properties of exosomes like immunoaffinity, size, and density	Fast, low cost, portable, easy automation and integration, high portability, but low in sample capacity and no isolation standard	Low recovery and high specificity