Table 2.

EV characterization methods.

Method	EV Information	Disadvantages	Ref.
TEM	Structure Shape Size Using gold particle conjugate Ab can allow the identification of EV specific markers	Does not allow precise quantification Requires trained personnel Not widely available	[21,22,23]
AFM	Structure (is able to provide sub-structural information) Shape Size	Does not allow precise quantification Requires trained personnel Not widely available	[22,23]
DLS	Size distribution Quantification	Can misrepresent EV concentration in non-processed or complex biofluids	[24]
NTA	Size distribution Quantification	Can misrepresent EV concentration in non-processed or complex biofluids	[24]
WB	EV specific proteins	Does not allow quantification	[27]
PCR	Based on the used method (e.g.,: PCR vs RT-PCR) can identify specific nucleic acids in the EV cargo	Standard PCR could be inappropriate if starting nucleic acid concentration is too low	[25,28,29]
FC	Specific markers on EVs New generation FC is able to quantify EVs	Old generation FC can only analyze bead conjugated EVs	[25,26]
OMICS based techniques	Allow EV DNA, RNA, protein, and lipid profiling	High costs and resource availability	[25,30,31]

TEM: Transmission Electron Microscopy, AFM: Atomic Force Microscopy, DLS: Dynamic Light Scattering, NTA: Nanoparticle Tracking Analysis, WB: Western Blot, ELISA: Enzyme linked immune-adsorbent protein assay, PCR: Polymerase Chain Reaction, FC: Flow Cytometry.