Exosomes: A Paradigm in Drug Development against Cancer and Infectious Diseases

Table 1

Exosomes isolation methods and mechanisms with specificity and demerits.

Methods	Steps	Mechanism	Specificity	Demerit	Ref.
Differential centrifugation	(i) 300 ×g (10 min); (ii) 1000 ×g to 20000 ×g (30 min); (iii) 100,000 ×g (60 min)	Based on centrifugal force	Common method to isolate exosomes from biological fluids	Yield lower when sample is; viscous	[6]
Density gradient	(i) 30% sucrose gradient; (ii) Differential centrifugation	Based on centrifugal force and density gradient	Separate low-density exosomes from high density contaminants and vesicles	Sensitivity high with centrifugation time	[7]
Size exclusion chromatography	(i) Sample applied on column packed with specific designed porous beads that allow elation only exosomes, without centrifugal force	Based on porosity of materials	Centrifugal force sensitive vesicles isolate this method and specific beads used for specific size. multiple biological samples can run together in this method	Long time taking procedure	[8]
Filtration	(i) Exosomes separate from the high molecular weight proteins and fatty acids	Based on membrane materials and porosity	Easily separate the soluble molecules and small particles from exosomes	Exosomes attached with membranes and lost the yield and original size	[9]
Polymer-based precipitation	(i) Biological fluid mixing with polymer; (ii) Incubation till precipitation; (iii) Centrifugation at low speed.; (vi) Resuspend in PBS	Based on polymer materials and precipitation	The advantages of precipitation include the mild effect on isolated exosomes and usage of neutral pH	Polymer-based precipitation and co-isolation of contaminants, like lipoproteins. In the presence of polymer material, not compatible with downstream analysis	[10, 11]
Immunological separation	(i) Magnetic beads bound to the specific antibodies; Example: ELISA-based separation method	Based on antibody receptor interaction	Methods for characterization and quantification of protein involve in selective subtypes of exosomes	Method is not applicable for large volumes	[7]
Isolation by sieving	(i) Sample sieving via a membrane; (ii) Perform filtration with pressure; (iii) electrophoresis	Based on sieving size and pressure	Short separation time with high purity of exosomes	Low recovery rate	[12]
Cell sorting	(i) Sample incubation 4 h with; magnetic beads; (ii) centrifugation 100,000 ×g (60 min)	Based on centrifugal and magnetic force	Short separation time with high purity of exosomes	Expensive and hectic	[13]