Transmission electron microscopy
For transmission electron microscopy (TEM), exosomes were isolated as
described and directly fixed in 200 μl of 2% paraformaldehyde. Exosome
preparations (20 μl) were allowed to adsorb in a 75 mesh Formvar/carbon
coated grid for 30 min at room temperature. Grids were then washed with
PBS (membrane side facing down) and dried using a filter paper. TEM was
performed using a Hitachi H-9000 transmission electron microscope at 300
kV, and images were captured using a slow-scan CCD camera.