FIGURE 5.

New paradigm of nanoparticle assessment using HS‐AFM. HS‐AFM imaging represents the continuity of nanotopological dynamics of sEV in response to different physicochemical parameters. The information gained is essential for sEV study in various aspects: (a) Structural dynamics of sEV‐based nanocarrier in drug release. (b) Material selection to produce sEV‐based products with high thermal stability (ex: sEV‐based COVID‐19 vaccine) for people in rural area with limited freezers and/or delivery service. (c) Quality control of sEV after isolation before downstream processes. (d) Real‐time observation of interaction between viral fusion protein and sEV layer during viral entry. sEV can be used to mimic endosome to provide a docking platform for viral fusion proteins during fusogenic transition triggered by low pH. (e) Nanoscopic assessment of pathogenic EVs. Helicobacter pylori EVs contain oncoproteins CagA and VacA, which are the etiological factors of chronic gastritis and gastric cancer. (f) Discovery of new nuclear transport mechanism. Non‐canonical nuclear transport of sEV contents (Corbeil et al., 2020) could be investigated using HS‐AFM in the near future. (AEC: anion exchange chromatography; INM: inner nuclear membrane; ONM: outer nuclear membrane; NPC: nuclear pore complex; NEI: nuclear envelope invagination; MT: microtubule; VAP‐A: (VAMP)‐associated protein A; ORP3: oxysterol‐binding protein (OSBP)‐related protein‐3; Rab7: late endosome‐associated small GTPase Rab7)