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Updated: Sep 27, 2025
Using Nanoplasmon-Enhanced Scattering and Low-Magnification Microscope Imaging to Quantify Tumor-Derived Exosomes
Published on: May 24, 2019
Nanomechanical characterization of exosomes and concomitant nanoparticles from blood plasma by PeakForce AFM in
Viktor Yu Bairamukov1, Anton S Bukatin2, Roman A Kamyshinsky3
1Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia.
Background:
To date, EVs characterization techniques are extremely diverse. The contribution of AFM, in particular, is often confined to size distribution. While AFM provides a unique possibility to carry out measurements in situ, nanomechanical characterization of EVs is still missing.
Methods:
Blood plasma EVs were isolated by ultracentrifugation, analyzed by flow cytometry and NTA. Followed by cryo-EM, we applied PeakForce AFM to assess morphological and nanomechanical properties of EVs in liquid.
Results:
Nanoparticles were subdivided by their size estimated for their suspended state into sub-sets of small S1-EVs (< 30 nm), S2-EVs (30-50 nm), and sub-set of large ones L-EVs (50-170 nm). Non-membranous S1-EVs were distinguished by higher Young's modulus (10.33(7.36;15.25) MPa) and were less deformed by AFM tip (3.6(2.8;4.4) nm) compared to membrane exosomes S2-EVs (6.25(4.52;8.24) MPa and 4.8(4.3;5.9) nm). L-EVs were identified as large membrane exosomes, heterogeneous by their nanomechanical properties (22.43(8.26;53.11) MPa and 3.57(2.07;7.89) nm). Nanomechanical mapping revealed a few non-deformed L-EVs, of which Young's modulus rose up to 300 MPa. Taken together with cryo-EM, these results lead us to the suggestion that two or more vesicles could be contained inside a large one being a multilayer vesicle.
Conclusions:
We identified particles similar in morphology and showed differences in nanomechanical properties that could be attributed to the features of their inner structure.
General Significance:
Our results further elucidate the identification of EVs and concomitant nanoparticles based on their nanomechanical properties.
