Table 2.

Forms of cell-free miRNAs.

Forms of Binding	References
Membrane-coated microparticles
Apoptotic bodies (0.1–5 µm)	[15,16,17]
Microvesicles (>0.5 µm)	[17,18,19,20,21,22,23]
Ectosomes (100–600 nm)	[24]
Oncosomes (1–10 µm)	[17,25,26]
Exosomes (30–150 nm)	[17,18,22,24,27,28,29,30,31,32,33]
Specific microvesicles (prostasomes (50 nm–0.5 μm), melanosomes (>0.5 µm), ‘platelet dust’ (~130–500 nm))	[33,34,35,36,37]
Membrane-free microparticles
High-density lipoproteins (HDL)	[23,38,39,40,41,42]
Low-density lipoproteins (LDL)	[39,40,42]
Various RNA-binding proteins (for example, AGO1, AGO2, nucleophosmin 1 (NPM1), Tamm-Horsfall protein (THP), etc.)	[23,43,44,45,46,47,48,49]
Exomeres (~35 nm (<50 nm))	[50,51]
miRNAs associated with the surface of blood cells	[27,32]