Nanoelectrical characterization of individual exosomes secreted by Aß42-ingested cells using electrostatic force microscopy.

ABSTRACT

Quantifying the physical properties of individual exosomes containing amyloid-ß42 (Aß42) is crucial for a better understanding of an underpinning mechanism of Alzheimer's disease expression which is associated with the Aß42 transfer. Because of the lack of proper tools, however, there have been very few studies on how the amount of Aß42 affects the physical properties of exosomes. To answer the question, we investigated the physical properties of exosomes secreted by neuroblastoma by probing individual exosomes using electrostatic force microscopy. Interestingly, we observed that when the higher concentration of Aß42 oligomers was fed to cells, the higher surface charge of the exosomes appeared. This result indicates that the exosomes contain more Aß42 with the increase in Aß42 concentration in cell media, implying that they serve as transport vesicles for Aß42. Our approach could help to better understand how the neuronal exosomes are related to the propagation of neurodegenerative diseases and to seek how to make an early diagnosis of those diseases.