Nanomechanical characterization of exosomes and concomitant nanoparticles from blood plasma by PeakForce AFM in liquid

• Published in: Biochimica et biophysica acta. General subjects Vol. 1866; no. 7; p. 130139
• Main Authors: Bairamukov, Viktor Yu, Bukatin, Anton S., Kamyshinsky, Roman A., Burdakov, Vladimir S., Pichkur, Evgeny B., Shtam, Tatiana A., Starodubtseva, Maria N.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2022
• Subjects: Atomic force microscopy; blood plasma; Elastic Modulus; Exosomes; Extracellular vesicles; flow cytometry; liquids; Microscopy, Atomic Force; modulus of elasticity; Multilayered vesicles; Nanoparticles; Plasma; Quantitative nanomechanical mapping exosomes; The Young's modulus; ultracentrifugation; Atomic force microscopy; EVs; Extracellular vesicles; AFM; Quantitative nanomechanical mapping exosomes; The Young's modulus; PeakForce QNM; Multilayered vesicles
• ISSN: 0304-4165; 1872-8006; 1872-8006
• DOI: 10.1016/j.bbagen.2022.130139

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. 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. 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. We identified particles similar in morphology and showed differences in nanomechanical properties that could be attributed to the features of their inner structure. Our results further elucidate the identification of EVs and concomitant nanoparticles based on their nanomechanical properties. [Display omitted] •Using PeakForce QNM, nanoparticles having unique sets of geometrical and mechanical properties were detected in human plasma•Large (50–170 nm) exosomes, including multivesiclar ones, were highly heterogeneous in nanomechanical properties•Non-membranous particles (<30 nm) differed from small exosomes (30–50 nm) by higher elastic modulus and less deformation