Results of STB-EV characterization. Figure 2A and 2D show the NTA results of S STB-EVs (2D) and m/lSTB-EVs (2A). Figure 2B,2C,2E and 2F displays representative transmission electron microscopy (TEM) images with wide view (2B and 2E), medium/large STB-EVs (2C), and Small STB-EVs (2F).