Table 2 Several methods for the isolation of Exos

Differential ultracentrifugation

Size, and shape

The large content of Exos, low cost, absence of chemical reagents, and high quality (gold standard)

Time-consuming, not suitable for a small volume of biomaterial, isolation based on sedimentation rates, shape can deform

Density gradient centrifugation

Density, and size

single centrifugation step,

The time of centrifugation should be optimized. prolonged centrifugation leads to sedimentation of all components, low-productive, size-separation methods need to purify Exos, and shape can deform

Isopycnic gradient centrifugation

floatation densities

Single centrifugation step, particles stop in the final position

Time-consuming, low-productive, size-separation methods need to purify exosomes, shape can deform

Ultrafiltration

Size

Low consumption, high output, convenience, the integrity of exosomes, gradual removal of particles

Particles may attach to the filter membrane, Low purity, shape can deform

Immunoaffinity capture

Exosomal surface markers

High specificity and purity, low contamination

Expensive, time-consuming

Magnetically activated cell sorting (MACS)

Charge, magnetic beads

a quick, reliable method, with high purity, may be used for clinical approaches

Relatively expensive and time-consuming

Size-exclusion Chromatography

Size, weight, hydrodynamic radius

High purity, fast

Low purity and contamination with other molecules, low yield, the influence of external force

Microfluidics

Physicochemical properties

Automated, fast, cheap

No standardizing, no clinical

Polymer-based precipitation

Exo aggregation in the presence of precipitating agents

High functional and morphological quality, large volumes of biomaterial, much cheaper

Low purity, lack of isolation from other components, poor solubility of precipitated aggregates