TABLE 2.

Platforms for isolating exosomes directly from bodily fluid samples that are routinely collected in clinical settings.

Isolation technique	On-chip pre-treatment	Property of separation	Specimen type	Sample volume (µl)	Isolation time (min)	Particle size (nm)	Recovery rate
Tilted-angle standing surface acoustic wave (Reátegui et al., 2018)	None	Particle size, density and compressibility of particles and fluid	Whole blood	100	25	75–125	82.4%
On-disc AAO membrane filtration (Sunkara et al., 2019)	Centrifugal disc plasma separation	Particle size	Whole blood	30–600	36	100–350	76–88%
Standing surface acoustic waves (Wang et al., 2020)	None	Particle size, density and compressibility of particles and fluid	Saliva	NA	10–20	20–250	NA
DC electrophoresis-assisted filtration (Davies et al., 2012)	None	Size and electrophoretic mobility	Whole blood	240	120	NA	1.5%
Immunoaffinity (Chen et al., 2019)	Size exclusion membrane filtration	Affinity	Whole blood	20	500	50–200	45%
Immunoaffinity (Zhou et al., 2020)	Inertial separation	Affinity	Whole blood	75	78	50–200	NA
DEP (Lewis et al., 2018)	None	Dielectric properties, shape and size of particles in fluid	Whole blood	25	20	NA	NA

Automated on-chip pre-treatment involved removing components of whole blood to simplify recovery of exosomes. Isolation time includes any required pre-treatment. AAO, Anodic aluminium oxide; DC, Direct current.