Table 2.
Advantages and disadvantages of traditional techniques to detect EVs.
| Techniques | Principle | Advantages | Disadvantages |
|---|---|---|---|
| TEM (23, 50, 58) | Scattered electron beam | High resolution; with capabilities to image <1 nm particles; |
Lengthy sample preparation and prone to affect the morphology and the size distribution of EVs; lack of multi-parametric phenotyping; low throughput |
| DLS (54, 59) | The intensity of the scattered light caused by the Brownian motion of the particles | High sensitivity; fast; |
The accuracy of detection signal is easily affected by the interference of contaminants; lack specificity |
| FCM (54, 58, 59) | Fluorescent signal and scattered light signal | High throughput; fast; enable individual EVs to be resolved and different surface markers to be measured per EV |
Poor reproducibility; particles <100 nm could not be detected; scatter resolution; |
| NTA (50, 54) | Laser light scattering and the Brownian motion of particles | Relatively high throughput; have the appropriate resolution for single EV particle analysis |
Time-consuming; lack of essential standardization; manual operation leads to human error; poor reproducibility |
| RPS (50, 54, 59) | Resistance pulses caused by particles passing through the pore | High accuracy; fast; high throughput; low sample volume required |
Relatively low stability and sensitivity due to the blockage of pores; multiple pore sizes are required; lack of multi-parametric phenotyping |
| WB (23, 60, 61) | Specific EVs marker proteins | High sensitivity and specificity; can provide useful information on the quantification of different proteins |
Time-consuming; semi-quantitative; cannot provide information on individual EV; cannot distinguish different EVs subtypes |
| ELISA (58, 62) | Binding of antibodies | Simple operation; high sensitivity and specificity; fast; high-throughput |
Cannot obtain information on the size distribution of EVs; poor reproducibility; high background signal; the result is susceptible to temperature and time |
EVs, extracellular vesicles; TEM, transmission electron microscopy; DLS, dynamic light scattering; FCM, flow cytometry; NTA, nanoparticle tracking analysis; RPS, resistive pulse sensing; WB, western blotting; ELISA, enzyme linked immunosorbent assay.