Table 2.

New technologies for exosomal protein detection

Methods	Exosome sources	Sample volume	Sensing mechanism	Sensing substances	Detection limit	Ref.
Colorimetric Detection	MCF-7 cells and breast cancer patient’s serum		H2O2-mediated oxidation of TMB	s-SWCNTs; CD63-specific aptamer	5.2 × 105 particles/μL	[109]
	Cell-culture medium and prostate cancer patient’s plasma	500 μL	H2O2-mediated oxidation of TMB	Aptamer-capped Fe3O4 nanoparticles	3.58 × 106 particles/mL	[72]
	Urine	100 mL	H2O2-mediated oxidation of TMB	Biotinylated anti-CD63 antibody; streptavidin-labeled HRP	35.0 AU/mL	[76]
	MCF-7 cells and cancer patient’s serum	100 μL	H2O2-mediated oxidation of TMB	CD9, CD63 antibody mixture; HRP-labeled secondary antibody	2.2 × 104 particles/μL	[110]
	BeWo cell		H2O2-mediated oxidation of TMB	Au-NP; Fe2O3NC	103 exosomes/mL	[148]
Fluorescence Detection	Plasma specimens from NSCLC and OVCA patients	30 μL	Chemifluorescence reagents	EpCAM, IGF-1R or CA125 antibodies; AP-conjugated secondary antibody, and the DiFMUP substrate	0.281 pg/mL; 0.383 pg/mL	[36]
	SKOV3 cells and plasma of OVCA patients	10 μL	The reaction of SβG with FDG	Biotin conjugated detection antibodies and streptavidin conjugated SβG	21 exosomes/μL	[149]
	MCF-7 and MDA-MB-231 cell culture medium	1 mL	Fluorescent carbocyanine dye (DiO)	CD63 antibody functionalized microbead and DIO labelling		[150]
	Cell culture supernatant and serum from pancreatic cancer patients		Fluorescent carbocyanine dye (DiO)	CD63 antibody-functionalized EXOchip		[20]
	MCF-7 cells and blood samples from cancer patients	100-300 μL	Fluorescent second antibody	Anti-EpCAM antibody and Alexafluor®647-conjugated secondary antibody		[59]
	Cell-culture medium and plasma from breast cancer patients		Fluorescent second antibody	CD63 antibody-coated magnetic beads; fluorescent dye-conjugated antibodies	107 particles/μL	[151]
	A549 cancer cell line and plasma samples of lung cancer patients	0.5 μL	Fluorescent aptamer	TMR-aptamer	500 particles/μL	[152]
	Serum samples		Fluorescent aptamer	CD63 aptamer-modified magnetic beads; Cy3-labeled short sequence	1.0 × 105 particles/μL	[126]
	Cancer cell line and plasma samples	500 μL	Fluorescent aptamer	TPE-TAs/aptamer complexes; graphene oxide surface	3.43 × 105 particles/μL	[99]
	MDA-MB-231 cell-culture medium and plasma from breast cancer patients	80 μL	Fluorescence quenching	GPC-1 antibody coated magnetic beads; CD63 aptamer	6.56 × 104 particles/μL	[84]
	Cancer cell line and serum samples		Fluorescence quenching	FAM-labeled aptamers; graphene oxide	1.6 × 105 particles/mL	[113]
	Cancer cell line and blood samples		Fluorescence quenching	Anti-CD63-PE/MoS2–MWCNT	14.8 × 105 particles/mL	[153]
Electrochemical Detection	Ovarian cancer cell lines and plasma from patients with ovarian cancer	10 μL	Integrated magneto-electrochemical sensor	Immunomagnetic beads; HRP-labeled secondary antibody	3 × 104	[128]
	Plasma samples	20 μL	Electrochemical biosensor	Immunomagnetic beads; probing antibodies		[129]
	Cell-culture medium and blood samples from breast cancer patients		Electrochemical biosensor	Anti-PD-L1-linked DNA strand; PVP@HRP@ZIF-8	334 particles/mL	[114]
	HepG2 cells and human serum of liver cancer patients	30 μL	Aptamer-based biosensors	CD63 aptamer and mimicking DNAzyme sequence	4.39 × 103 particles/mL	[65]
	Culture medium of HepG2 cells		Aptamer-based biosensors	NTH-assisted aptasensor	2.09 × 104/mL	[154]
	Cell-culture medium and serum		Aptamer-based biosensors	Aptamer-magnetic bead bioconjugates; electroactive Ru (NH3)63+	70 particles/μL	[155]
	Cellular supernatant and human plasma samples		Aptamer-based biosensors	anti-CD63 antibody modified gold electrode and a gastric cancer exosome specific aptamer	9.54 × 102/mL	[156]
	Human hepatoma cell lines MHCC97H/L and mouse melanoma cell lines B16-F1/10		Antibody microarray SPRi sensor	Anti-CD9, CD41b,21 and tyrosine kinase receptor MET8a antibodies immobilized gold-coated glass sensor chip		[157]
SPR Detection	MCF-7 breast cancer cells and MCF-10A normal breast cells		SPR-based aptasensor	Dual gold nanoparticle-assisted signal amplification	5 × 103 exosomes/mL	[158]
	Human NSCLC cell lines, normal lung cell and plasma	1.5 mL	Bioaffinity interactions of antibodies and different recognition sites	Antibodies modified-gold chip and different recognition sites	104 particles/μL	[159]
	Urine samples from lung cancer patients and controls	500 μL	SPR-induced improved scattering intensity	Anti CD81/LRG1 antibody modified nanoporous gold nanocluster membrane; second antibody-conjugated Au nanorod probes	< 1000 particles/mL	[58]
	Breast cancer cell line and serum	250 μL	SPR-induced improved scattering intensity	Anti-HER2-functionalised SPR chip	8280 exosomes/μL	[160]
	Cancer cells and serum and the CSF of an orthotopic mouse model		Strong localization of surface plasmon polaritons	TIC-AFM and TiN–NH-LSPR biosensors	5.29 × 10−1 μg/ml; 3.46 × 10 -3 μg /ml	[161]
	Breast cancer cells and normal breast cells; plasma from HER2-positive breast cancer patients		Raman reporters	Gold-coated glass microscopy slide; QSY21-coated gold nanorods	2 × 106/mL	[134]
SERS	Plasma of cancer patients	400 μL	P-O bond signature	Beehives-like Au-coated TiO2 macroporous inverse opal		[117]
	Cell-culture medium and serum sample	4 μL	MBA signature	Fe3O4@TiO2 nanoparticles; anti-PD-L1 antibody modified Au@Ag@MBA	1 PD-L1 exosome/μL	[90]
	Normal and lung cancer cell lines; plasma		Deep learning	Deep learning model		[162]
	Cell-culture medium; serum and plasma	< 1 μL	Enrichment of aptamer-bound EVs	Seven aptamers targeting specific proteins; machine-learning algorithm	3.3 × 103/μl	[68]
CRISPR/Cas-assisted detection	A549 cell-culture medium and serum from lung cancer patients		CRISPR/Cas12a	CD63 aptamer; CRISPR/Cas12a	Linear range of 3 × 103–6 × 107 particles/μL	[136]
	SUNE2 cell-culture medium and serum from NPC patients	50 μL	CRISPR/Cas12a	Nucleolin and PD-L1 aptamers; CRISPR/Cas12a	102 particles/μL	[137]
	SUNE2 cell-culture medium and serum from NPC patients		CRISPR/Cas12a	CD109 and EGFR aptamers; CRISPR/Cas12a	102 particles/μL	[138]
Single EV Analysis	Human serum	10 μL	Rolling circle amplification	ssDNA-assisted single EV detection platform	82 vesicles/μL	[139]
	T3M4 pancreas cancer line and serum from PDAC patients	10 mL	Flow cytometry	Aldehyde/sulfate latex beads; anti-GPC-1 antibody and Alexa-488-tagged antibody		[38]
	Breast cancer cell lines and serum of breast cancer patients	500 μL	Flow cytometry	Aldehyde/sulfate latex beads; anti-EpCAM or anti-HER2 antibody; Alexa-488- or − 594-tagged secondary antibodies		[141]
	Human cell lines and serum of glioma patients	250 μL	Flow cytometry	Aldehyde/sulfate latex beads; anti-EGFR or anti-CXCR4 antibody		[118]
	HCT15 cell-culture medium and plasma	500 μL	Nano-flow cytometry			[142]

OVCA Ovarian cancer, PGR Progesterone receptor, ESR1 Estrogen receptor 1, ERBB2 erb-b2 receptor tyrosine kinase 2