Table 4.
Classic immune analysis techniques for exosome proteins
| Method | Basic principle | Signal output | Sample volume (μL) | LOD (particles/mL) | Analysis time ≤ 2 h | Advantages | Disadvantages |
|---|---|---|---|---|---|---|---|
| Surface Plasmon Resonance (SPR) [141–145] | Binding between EV and sensor surface coated with specific antibody induces refractive index change. | Refractive index | 20 | 107 | yes | Label-free, monitor binding between exosome and antibody | require special instrument |
| Fluorescent Immuno Sorbent Assay (FLISA) [90, 146] | ELISA based method | Fluorescence | 1 | 1010 | no | High sensitivity | problem of auto fluorescence and fluorescence quenching |
| Time-Resolved Fluorescent Immuno Assay (TRFIA) [147] | Based on long half-life of europium | Phosphorescent molecules (like europium) | 100 | 1010 | no | More sensitive than ELISA | europium is harmful for health |
| Integrated Microfluidic Exosome Analysis Platform (IMEAP) [84, 148] | Combination of MAIA technique and microfluid | Fluorescence | 30 | 108 | yes | More capture surface than ELISA, micro fluid improves efficiency | _ |
|
Amplified Luminescent Proximity Homogeneous Assay (ALPHA) [149] |
EV pulls two beads as close as 200 nm, accepter beads uptake O2 from donor bead after being activated | Emitted light | 5 | 1010 | yes | High sensitivity and simple reaction system, signal amplification | signal fluctuation and hook effect |
| Micro-Nuclear Magnetic Resonance (μNMR) [150, 151] | Immunomagnetic nanoparticles binding to EV surface antigen induces magnetic field change | Magnetic susceptibility | 1 | 107 | yes | Simple operation | require special instrument |