TABLE V.

Summary of exosomes' isolation techniques and applications.

Isolation technique	Applications	Reference
Differential ultracentrifugation—conventional technique	The most common technique in research with limited clinical: Annexin V, the tetraspannin CD63, the heat shock protein Hsp70 and TSG101 Microfluidic platforms: porous microstructure/size filtration (not validated with clinical samples, and no analysis of cargo protein or RNA)	44, 282, 293, 299, 303, and 331–337
Density gradient ultracentrifugation	Commercial kit-OptiPrep	303, 331, 338, and 339
Micro-/ultrafiltration and other size exclusion methods	Isolation of exosomes from small (0.5–10 ml) samples Microfluidic platforms: porous microstructure/Size filtration (no clinical validation)	44, 282, 299, 332, 335, 337, and 340–343
Solvent precipitation	ExoQuick™ (System Bioscience)	344 and 345
	Total Exosome Isolation™ (Life Technologies)
	Exospin (Cell Guidance System) commercial kit
Immunoaffinity capture (IAC)	Liquid biopsy	11, 281, 296, 303, 312, 314, 318, 319, 324, and 345–350
	Microfluidic platforms: •“ExoChip”: pancreatic cancer (CD63, Rab5)—miRNA •The optimized iMER assay: glioblastoma—adapted nano-IMEX—ovarian cancer •ExoSearch chip—ovarian cancer (CA-125, EpCAM, CD24) •On-chip immunofluorescence: non-small-cell lung cancer (IGF-1R) •Immunocapture (IC) on channel surface platform: intra-vesicular protein and mRNA •IC on beads with inertial sorting platform: melanoma, breast cancer (miRNA-222) •nPLEX—nanoplasmonic exosome sensor: ovarian cancer (EpCAM; CD24) •Nano-IMEX
	Nanoshearing chip, electrohydrodynamic flow assisted IC: high sensitivity, inline detection
	Electric Field Induced Release and Measurement (EFIRM) technique: RNA and protein molecules
Field flow fractionation (FFF)	High consistency and specificity	307, 323, 351, and 352
	In vivo—mouse melanoma B16-F10 cell line •Coupled to affinity methods for increased specificity as one label free isolation device •Breast cancer (HER1+, HER2+) •Functional characterization of exosomes
Nanoparticle tracking analysis	EC-EXs and EPC-EXs:CD105/CD144, CD34/ KDR	353–356
Size exclusion chromatography (SEC) and mini-SEC	Mini-SEC: solid tumor (head and neck squamous cell carcinoma) and acute myeloid leukemia (AML): CD9, TSG101; TGF-b1-associated pro-peptide and latency-associated protein (LAP), PD-1, PD-L1, COX-2, FasL, or CD39/CD73 ecto-enzymes; leukemia blast-relevant proteins: CD34, CD44, CD96, CD123 and CLL-1; TEX alter functions of activated NK cells or T cells	333 and 357–360