Figure 1.
Cryo-TEM images of circulating MPs withdrawn from the blood of a healthy subject.
(a) MPs are seen to be flexible as they can be compressed between two surfaces; (b) shedding of smaller vesicles from an MP; (c) smaller vesicles incapsulated inside bigger MPs, creating multilayered MPs. Inner vesicles deform according to the outer MP membrane shape (arrows).
Figure 2.
Cryo-TEM images of circulating MPs after storage at–80°C prior to specimen preparation.
(a) MP inner contents are filling the sample medium; (b) MP breakage is documented; (c) pin-shaped nanoparticles, possibly membrane fragments seen side-on (arrows).
Figure 3.
Cryo-TEM images of THP-1 derived MPs.
(a) Heavily granulated MP; (b) multilayered MP with two inner vesicles; arrow indicates a very smooth, almost empty MP; (c) arrows show nanoparticles, probably glycoproteins, decorating the MP membrane; (d) vesicle shedding from the MP membrane.
Figure 4.
Cryo-TEM images of THP-1 derived MPs after freezing to–80°C.
(a) Sample freezing induced numorous artifacts such as the fomration of massive membrane structures enclosing smaller MPs and membrane breakage (arrow); (b) elongated nano-fibers are seen, possibly DNA or RNA strands explled from the broken MPs; (c) sample with 10% v/v DMSO; although the MP morpholgy seems intact, severe e-beam radiation damage is seen; (d-e) samples that were rapid-cooled using LN2 before storage at -80°C; MPs showed the same morphology seen in the fresh samples.
Figure 5.
Cryo-TEM images of MDA-231 derived MPs.
(a) Granulated and smooth MPs; (b) bilayered MP with nanoparticle decoration on its membrane; (c) multilayered MP with three inner vesicles; (d) two dashed lines clearly show the phospholipid bilayer stucture of the MP membrane.
Figure 6.
FACS analysis of HVT cell-derived MPs.
(a) MP size evaluation gate (R1) established using 0.78 µm beads with side scatter (SS) and forward-scatter (FSC) in logarithmic scale; (b) fluorescence intensity of green beads (FITC); (c) non-labeled HVT-MP population; (d) non-labeled HVT-MPs at gate R1 show no fluorescence intensity (negative control); (e) HVT-MPs green labeled by Calcein AM fluorescent dye at gate R1; (f) fluorescence intensity–89% of MPs at gate R1 were green labeled.
Figure 7.
Cryo-TEM images of HVT cell-derived MPs; most of MPs were multilayered.
Figure 8.
TEM image of a uranyl acetate negative-stained sample of MDA231 MPs: Multilayered MP morpholgy is seen.
Arrows indicate vesicles seen in the main MP.
Figure 9.
Cryo-TEM images of MDA231 MPs separated by filtration: (a) Only a few MPs showed a bilayered morphology; (b) contamination is dominating the sample, probably medium proteins that did not wash out.
Figure 10.
Cryo-TEM images of MDA231 MPs separated by dialysis: All MPs were spherical; no major contamination was seen.