Characterization of Extracellular Vesicle Topography by AFM

Atomic force microscopy was performed to characterize the topography of extracellular vesicles as described previously [14 (link)]. Briefly, 20µL (9–12 × 10¹¹ EVs/mL) of EV sample was deposited on APS mica for 20 min at room temperature. Then 200 μL of the PBS buffer was added to the sample. The sample was then subjected to atomic force microscopy (AFM) imaging using the Asylum Research MFP3D (Santa Barbara, CA, USA) instrument. Imaging was performed in tapping mode at room temperature. An MSNL probe with cantilever “E” (Bruker Corporation) was employed for imaging. The nominal spring constant of the MSNL “E” cantilevers was ∼0.1 N/m.