Table 2.
Principles and characteristics of characterization methods of EVs.
| Type | Method | Principle | Advantage | Disadvantage |
|---|---|---|---|---|
| By physical property (size and morphology) | TEM; Cryo-EM; SEM | Electron radiation | High resolution | High cost; Low throughout; Complex sample processing; Not quantitative |
| AFM | Measuring the force between the probe and sample | High resolution | High cost; Low throughput; Not quantitative | |
| DLS | Measuring the scatter light from EVs in Brownian motion | Easy to operate; Low cost | Not quantitative; Not suitable for polydisperse sample | |
| NTA | Capturing the Brownian motion of individual particle | Quantitative; Suitable for monodisperse and polydisperse samples | Affecting by the instrument parameter settings | |
| Imaging FCM | Based on FCM and fluorescence imaging | Sensitive; High throughput; Low sample volume | High cost; Professional personnel | |
| Nano-FCM | FCM based on nanopore | Quantitative; Low sample volume | High cost; Professional personnel | |
| CLSM | Microscopy imaging after fluorescent label | High resolution; Dynamic visualization | Not quantitative; High cost | |
| TRPS | Based on the changes of resistance pulses of a single particle through a pore | Quantitative; Low sample volume | Clogging the pore by large particle | |
| TSPR | Based on free electrons collectively oscillate under the Incident light field | Quantitative; Low sample volume | Noise interference by containments | |
| By compositional property (protein) | ELISA | Immunoaffinity | High throughput; Fast | High cost; Low specific |
| SDS-PAGE | Characteristic absorption in the visible spectrum | Easy to operate; Fast | Not quantitative; Low detection limit | |
| WB | Immunoaffinity | Quantitative; Specific | High cost; Time-consuming | |
| MS | q/e analysis of small fragments | High specific; Quantitative | High cost; Professional personnel | |
| By compositional property (nucleic acid) | UV‒Vis | The characteristic absorption peaks | Low cost; Easy to operate; Fast | Low specific |
| qPCR | Amplification of specific genes | High throughput; Low sample volume | Only suitable for known genes | |
| microarray | Based on the principle of base pairing | High throughput; Specific | High cost; Professional personnel | |
| NGS | Fluorescence sequencing after RNA reverse transcription | Sensitive; Specific | Low throughput; High cost | |
| By compositional property (lipid) | GC–MS, LC‒MS | q/e analysis of small fragments | High specific; Quantitative | High cost; Professional personnel |