Table 2.
Exosome detection and analysis in microfluidic platforms.
| Exosome detection approach | Sample (pre-treatment) * | Sensitivity/detection limit | EV size** [nm] | Reference |
|---|---|---|---|---|
| Fluorescence | ||||
| ExoChip: Fluorescent staining, detection via conventional plate reader | Serum | 0.5 pM fluorescence sensitivity | ~30–300 | Kanwar 2014 [72] |
| ELISA-based (IGF-1R, p-IGF-1R) chemifluorescence imaging | Plasma (pre-mixed with capture beads) | 0.281 pg/mL (IGF-1R), 0.383 pg/mL (p-IGF-1R) | ~40–150 | He 2014 [57] |
| RInSE: Inertial solution exchange for continuous isolation of affinity-capture (EpCAM) microbeads | Blood (RBC lysis, centrifugation, incubation with capture beads and label) | NA | ~30–120 | Dudani 2015 [77] |
| ExoSearch: Fluorescently labeled antibodies (CA-125, EpCAM, CD24), multiplex fluorescence imaging | Plasma | 750 exosomes/μL | ~50–250 | Zhao 2016 [80] |
| Nano-IMEX: Enhanced capture and detection via nanostructured surface coating, ELISA-based (CD9, CD81, EpCAM) fluorescence imaging | Plasma (10X dilution) | ~50 exosomes/μL | <150 | Zhang 2016 [74] |
| μMed: ELISA-based (GluR2) optofluidic detection via smartphone | Mouse serum | 10000 exosomes/μL | ~117 | Ko 2016 [81] |
| Nano flow cytometer, imaging of single fluorescently labeled vesicles passing through nanochannels | Cell culture supernatant (centrifugation, 0.2 μm filter, ultracentrifugation, fluorescence labeling) | Single particle sensitivity, 170 fM LOD for vesicle concentration | ~<300 | Friedrich 2017 [107] |
| Fluorescently labeled antibodies (EpCAM, HER2), fluorescence imaging_ | Plasma (incubation with capture particles) | NA | <100 | Fang 2017 [78] |
| Colorimetric | ||||
| Nanoshearing-enhanced capture and detection, ELISA-based (CD9, HER2) colorimetric sensing | Serum | 2760 exosomes/μL | ~30–350 | Vaidyanathan 2014 [73] |
| Exodisc: ELISA-based (CD9, CD81) colorimetric detection | Urine | NA | 20–600 | Woo 2017 [85] |
| ELISA-based (CD63) colorimetric detection aided with smartphone imaging | Urine (centrifugation, 0.22 μm filter) | NA | 155 | Liang 2017 [84] |
| Other immunoaffinity-based | ||||
| μNMR: Labeling with target-specific (CD63, EGFR, EGFRvIII, IDH1 R132H, PDPN) magnetic nanoparticles, on-chip NMR detection | Plasma (0.2 μm filter, differential centrifugation) | 10000 microvesicles | 50–150 | Shao 2012 [108] |
| nPLEX: Functionalized gold surface with nanohole arrays (EpCAM, CD24, CD63), portable SPR detection | Ascites fluid (0.2 μm filter) | ~3000 exosomes (670 aM) | ~20–260 | Im 2014 [44] |
| Microcapillary electrophoresis of immunolabeled EVs (CD63, CD44), laser dark-field microimaging | Mouse plasma | NA | ~50–450 | Akagi 2015 [109] |
| SPR detection of clinically relevant exososmes (HER2) | Serum | ~2070 exosomes/μL | ~30–300 | Sina 2016 [75] |
| Other | ||||
| Continuous electrical detection during transit through a nanoconstriction | Mouse plasma (2.5X dilution, centrifugation, pre-mixed with calibration particles) | Single particle sensitivity | ~50–100 | Fraikin 2011 [111] |
| Electrical detection of RNA by binding to complementary miR-550 probes on an ion exchange nanomembrane surface | Cell media | 2 pM of miRNA | ~20–50 | Taller 2015 [112] |
| iMER: Detection of mRNAs (EPHA2, EGFR, PDPN, MGTM, APNG) via on-chip RT-qPCR | Serum (0.8 μm filter) | NA | ~ 100 | Shao 2015 [79] |
| Aptamer probes immobilized on gold electrodes (CD63), electrochemical detection | Cell culture supernatant (0.22 μm filter, centrifugation, exosome isolation kit) | 1000 particles/μL | ~100 | Zhou 2016 [82] |
NA: not available. RBC: red blood cell. BSA: bovine serum albumin.
*
Sample is of human origin unless otherwise stated.
**
Size of isolated particles is typical and it might not correspond precisely to the sample and operating conditions shown.