Force measurements on natural membrane nanovesicles reveal a composition-independent, high Young's modulus

Abstract

Mechanical properties of nano-sized vesicles made up of natural membranes are crucial to the development of stable, biocompatible nanocontainers with enhanced functional, recognition and sensing capabilities. Here we measure and compare the mechanical properties of plasma and inner membrane nanovesicles ∼80 nm in diameter obtained from disrupted yeast Saccharomyces cerevisiae cells. We provide evidence of a highly deformable behaviour for these vesicles, able to support repeated wall-to-wall compressions without irreversible deformations, accompanied by a noticeably high Young's modulus (∼300 MPa) compared to that obtained for reconstituted artificial liposomes of similar size and approaching that of some virus particles. Surprisingly enough, the results are approximately similar for plasma and inner membrane nanovesicles, in spite of their different lipid compositions, especially on what concerns the ergosterol content. These results point towards an important structural role of membrane proteins in the mechanical response of natural membrane vesicles and open the perspective to their potential use as robust nanocontainers for bioapplications.

Competition between Bending and Internal Pressure Governs the Mechanics of Fluid Nanovesicles

“…Before such an indentation we always checked that we were working with a clean tip (Figure S2). As previously observed, 18,19 vesicles can withstand large deformations without permanent damage. This robustness is inferred from the lack of change in contact point after multiple indentations (Figure 2a) and confirmed by imaging afterward (Figure S3).…”

“…Moreover, the mechanical behavior identified here, such as the inflection at 0.35–0.40 R c and the strong tip size dependence, could potentially be useful to test the fluidity of the membrane of nanovesicles, since their occurrence is not expected for membranes with finite shear moduli. 19,36 …”

Stem Cell Extracellular Vesicles: Extended Messages of Regeneration

“…Tetraspanins play particularly prominent roles in cytonemes and EVs by giving them curvature and strength and by regulating the spacing, distribution, trafficking, and fusion of membrane proteins and their interacting partners (37). This naturally organized and interlaced membrane texture likely accounts for EVs being nearly as hard as viruses and about an order of magnitude harder than synthetic liposomes, inferred by their high elastic modulus and ability to deform elastically while maintaining vesicle integrity as measured by atomic force microscopy (38). Indeed, their intrinsic durability and natural biocompatibility may render EVs particularly suitable as delivery vehicles for natural and synthetic therapeutics.…”

“…The properties of EV membranes that provide them with excellent biocompatibility and greater durability (38), and the ease of genetically engineering EVs (19) compared to liposomes and nanoparticles, make EVs potentially useful carriers for diagnostic and imaging agents. We believe this use will increase in the near future.…”

Membrane remodeling and mechanics: Experiments and simulations of α-Synuclein

“…This technique has been used to characterize a variety of lipid systems ranging from synthetic liposomes (Fig. 8A) to synaptic vesicles [64–68,174–176]. AFM is capable of extracting material properties of extremely small vesicles, but like other approaches requires modeling of the force curves (Fig.…”