Imaging and mechanical analysis of single native exosomes by atomic force microscopy

Exosomes as the carriers of intercellular communications play an important role in the physiological and pathological processes of living organisms. Particularly, exosomes are present in nearly all biofluids and detecting the exosomes in the liquid biopsy has been a promising way to develop novel methods for detecting and monitoring human diseases such as cancer. Atomic force microscopy (AFM) offers a powerful tool to characterize the structures and mechanical properties of individual exosomes in their native states under aqueous conditions. In this chapter, the applications of AFM in the studies of single native exosomes are presented, mainly including exosome isolation methods, imaging exosomes in liquids, measuring the mechanical properties of exosomes, simultaneous structural and mechanical imaging of exosomes, and probing the molecular activities on the exosomal surface.